•ELEMENTS 


PHILOSOPHY, 

ARRANGED  UNDER  THE  FOLLOWING 

HE  ADS  t 


Matter  and  Motion, 
The  Universe, 
The  Solar  System, 
The  Fixed  Stars 


e      xe      tars, 

The  Earth  considered  as  a  Planet, 
The  Atmosphere, 


Meteors, 

Springs,  Rivers,  and  the  Sea, 

Fossils, 

Plants, 

Animals., 

The  Human  Frame, 


And 
THE  HUMAN  UNDERSTANDING, 


T  see  a  mighty  arm,  by  man  unseen, 
'•Resistless-,  not  to  be  controlled,  that  guides, 
"  In  solitude  of  unshar'd  energies, 
u  All  these  thy  ceaseless  miracles,  O  world!" 

C.  LAME- 


NEW-rORK: 


Printed  by  D.  &  G.  Bruce, 
FOR  J.  QSBQRN,  BOOKSELLER,  13  PARK, 

•      1808, 


CONTENTS;" 


Page 

Ckap.  I.  Matter  and  Motion  .  ,  . 11 

II.  The  Universe 24> 

III.  The  Solar  System 3f 

IV.  The  Fixed  Stars 57 

V.  The  Earth  considered  as  a  Planet  .  .    68 

VI.  The  Atmosphere 90 

VII.  Meteors •  .  .  .  , 105 

VIII.  Springs,  Rivers,  and  the  Sea 124 

IX.  Fossils 141 

X.  Plants    177 

XI.  Animals 200 

XII.  The  Human  Frame 234 

XIII.  The  Human  Understanding    ......  ^260 


984 


PREFACE. 

IN  an  age  like  the  present,  when 
the  growth  of  every  production  con- 
ducive to  the  interests  of  morality,  and 
a  more  extensive  knowledge  of  the 
Creator  through  the  medium  of  his 

O  'y 

tvorks,  is  recommended  and  publicly 
encouraged,  hut  little  need  be  offered 
by  way  of  apology  for  the  present 
Compilation.  One  important  object 
of  the  following  pages  was  to  present  ^ 
in  a  very  compact  and  comprehensive 
form,  an  interesting  and  connected 
account  of  those  laws  and  operaiions 
in  the  material  world  >  which >  under 
the  elaborate  pens  of  philosophical 
authors,  cover  an  extent  of  scientific 
ground  too  enlarged  for  the  commer- 
cial and  labouring  individual  to  tra- 
vel over ;— but  more  particularly  has 
this  little  compendium  been  arranged 
for  the  juvenile  inquirer,  who  either 
A 


PREFACE. 


from  a  premature  wish  to  anticijh 
the  result  of  deep  calculations, or  from, 
other  contingent  occupations,  would 
have  a  general,  yet  clear,  idea  of  ob- 
jects, which  zvithout  the  aid  of  philo- 
sophy he  cannot  understand.  To  en- 
able him  to  accomplish  this  desirable 
end,  the  following  pages  are,  as  far 
as  possible,  divested  of  the  technical 
difficulties  which  but  too  often  form 
impenetrable  barriers  to  the  expan- 
sion of  the  rising  mind.  While,  how- 
ever, they  endeavour  to  exhibit  in  a 
-^amiliar  manner  that  chain  of  con- 
nexion which  binds  and  unites  all  na- 
ture, they  will  by  no  means  supersede 
an  encouragement  to  penetrate  into 
those  sciences  whence  the  axioms, laws, 
and  calculations  which  relate  to  mat- 
ter and  motion  are  ascertained.. 

Having  notified  the  design  of  this 
little  manuel,  it  is  unnecessary  to  en- 
force  the  importance  of  the.  subject  of 
which  it  treats.  No  employment  sure- 


PREFACE.  7 

hj  yields  so  rich  a  'harvest  of  instruc- 
tion and  delight  to  a  rational  being 
as  that  of  surveying  the  wonderful 
works  of  tlic  Great  Creator -,  as  dis- 
played in  the  various  parts  of  the 
universe.  Such  employment  is  a  source 
of  never-failing  satisfaction  to  per- 
sons of  every  age ;  and  it  is  only  by 
acquiring  a  knowledge  of  nature,  and 
observing  the  contrivance  and  skill 
conspicuous  in  every  department  of 
creation,  that  we  are  enabled  to  form 
an  adequate  idea  of  the  attributes 
and  character  of  the  Supreme  Being. 
In  proportion  as  we  attain  a  know- 
ledge of  the  objects  around  us  they 
become  interesting  and  important. 
That  which  to  the  careless  and  un- 
enlightened spectator •,  appears  solita- 
ry and  detached,  having  no  other  con- 
nection with  the  rest  of  the  universe 
but  the  shadowy  andjleeting  relation 
of  co-existence,  zvill,  to  him  who  takes 
i  glimpse  into  the  general  economy 


$  PREFACE* 

of  nature*  declare  themselves  to  l>e 
ports  of  a  great  and  harmonious 
whole,  connected  by  general  laws,  and 
tending  fo  one  general  and  beneficent 
J);trp-jse>  and  cannot  fail  of  impres- 
sing him  with  a  wish  to  co-operate  in 
tins  glorious  plan,  by  acting  worthy 
of  the  place  he  holds  among  the  works 

&GO& 

Tn as  is  the  study  of  nature  calcu- 
lated to  eral1  the  mind,  and  reduce 
the  sinn  of  human  pride  and  igno- 
?  '  -  ,  and  ccmes  in  aid  of  that  self- 
abasement  which  the  great  duties  of 
Christianity  impose,  hy  teaching  man 
that,  though  he  stands  a  pinnacle  of 
power,  and  grasps  in  intellect  all  the 
prodigious  works  of  'creation,  he  is  but 
a  link  in  an  immeasurable  chain  that 
serve*  to  suspend  and  give  motion  to 
the  zoorks  of  Him  who 

Connects  each  being,  greatest  with  the  least, 
Made  beast  in  aid  of  man,  and  man  of  beast. 

Nor  is  it  as  a  moral  agent  only 


PREFACE. 


tnat  man  is  benefited  by  a  knowledge 
of  natural  philosophy  ;  it  teaches  him 
to  employ  the  powers  of  nature  to  the 
greatest  advantage  for  the  embellish- 
ment and  comfort  of  life,  and  extends 
his  empire  over  the  material  universe. 

Knowledge  of  this  kind,  therefore, 
is  the  most  valuable  that  man  can  ac- 
quire: it  enriches  his  life  with  conve- 
niences, enlarges  his  views,  and  lays' 
a  foundation  for  the  most  rational 
and  exalted  piety.  *(  The  universe 
(says  Boyle)  is  the  magnificent  tem- 
ple of  its  great  Author  ;  and  man  is 
ordained,  by  his  powers  and  qualifi- 
cations, the  high-priest  of  nature,  to 
celebrate  divine  service  in  this  temple 
of  the  universe." 

Let  him  then,  aspiring  to  the  dig- 
nity of  his  station,  assisted  by  the 
writings  of  modern  authors,  devote 
his  noblest  powers  to  the  investigation 
of  the  laws  of  nature  ;  and  evince  that 
he  is  not  in  vain  given  ability  to  be 


1O  PREFACE* 

wiser  than  the  fowls  of  heaven,  and 
to  have  more  understanding  than  the 
beasts  which  perish. 


ELEMENTS 


NATURAL  PHILOSOPHY, 


CHAP.  I. 

Of  Matter  and  Motion. 

MATTER  is  an  extended  solid*  sub- 
stance ;  which  being  comprehended  un- 
der distinct  surfaces,  makes  so  many  par* 
ticular  distinct  bodies. 

*  Solidity  is  not  here  considered  as  opposed  to 
fluidity,  but  as  that  property  which  every  body 
possesses  of  not  permitting'  any  other  substance  to 
occupy  the  same  place  with  it  at  the  same  time  ; 
so  that  both  water  and  air,  and  every  other  fluid, 
are  equally  solid,  in  this  sense  of  the  word,  with 
the  hardest  body.  By  solidity,  in  common  lan- 
guage, is  understood  the  property  of  not  being* 
easily  separated  into  parts  ;  and  therefore  the 
reader  must  be  careful  not  to  confound  the  mean- 
ing- of  the  popular  with  the  philosophical  terro* 


1 2  Matter  and  Motion. 

Motion  is  so  well  known  by  the  sight 
and  touch,  that  to  use  words  to  give  a 
clearer  idea  of  it  would  be  in  vain. 

Matter,  or  body,  is  indifferent  to  mo- 
tion or  rest. 

There  is  as  much  force  required  to 
put  a  body,  which  is  in  motion,  at  rest ; 
as  there  is  to  set  a  body,  which  is  at  rest, 
into  motion. 

No  parcel  of  matter  can  give  itself  ei- 
ther motion  or  rest ;  and  therefore  a  bo- 
dy at  rest  will  remain  so  eternally,  ex- 
cept some  external  cause  puts  it  in  mo- 
tion ;  and  a  body  in  motion  will  move 
eternally,  except  some  external  cause 
stops  it. 

A  body  in  motion  will  always  move 
on  in  a  straight  line,  unless  it  be  turned 
out  of  it  by  some  external  cause  ;  because 
a  body  can  no  more  alter  the  determina- 
tion of  its  motion  than  it  can  begin  it, 
alter  or  stop  its  motion  itself. 

The  velocity  of  motion  is  estimated 
by  the  time  employed  in  moving  over  a 
certain  space,  or  by  the  space  moved 
over  in  a  certain  time.  The  less  the  time, 
and  the  greater  the  space  moved  over,  the 
greater  is  the  velocity  ;  on  the  contrary, 


Matter  and  Motion.  13 

the  greater  the  time,and  the  less  the  space 
moved  over,  th*.  less  is  the  velocity*  Ev- 
ery body  in  motion  must  have  a  determi- 
nate velocity.  To  ascertain  the  degree 
of  this  swiftness  or  velocity,  the  space 
run  over  must  be  divided  by  the  time. 
For  example,  suppose  a  body  moves  over 
1000  yards  in  10  minutes,  its  velocity 
will  be  100  yards  per  minute,  because 
100  is  the  quotient  of  1000,  divided  by 
10.  If  we  would  compare  the  velocity 
of  twu  bodies  A  and  B,  of  v.hich  A 
moves  over  54  yards  in  9  minutes,  and 
B  96  yards  in  6  minutes,  the  velocity  of 
A  will  he  to  that  of  B,  in  the  proportion 
of  6  (the  quotient  of  54  divided  by  9)  to 
16  (the  quotient  of  96  divided  by  6.) 

To  know  the  space  run  over,  the  velo- 
city must  be  multiplied  by  the  time  ;  for 
it  is  evident,  that  if  either  the  velocity  or 
the  time  be  increased,  the  space  run  over 
will  be  greater.  If  the  velocity  be  doub- 
led, then  the  body  will  move  over  twice 
the  space  in  the  same  time ;  or  if  the 
time  be  twice  as  great,  then  the  space 
will  be  doubled  :  but  if  the  velocity  and 
time  be  both  doubled,  then  will  the 
be  four  times  as  great, 


14  Matter  and  Motion. 

It  follows  from  this,  that  when  two 
bodies  move  over  unequal  spaces  in  un- 
equal times,  their  velocities  are  to  each 
other  as  the  quotients  arising  from  divi- 
ding the  spaces  run  over  by  the  times. 
If  two  bodies  move  over  unequal  spaces 
in  the  same  time,  their  velocities  will  be 
in  proportion  to  the  spaces  passed  over. 
And  if  two  bodies  move  over  equal  spa- 
ces in  unequal  times,  then  their  respec- 
tive velocities  will  be  inversely  as  the 
time  employed  ;  that  is,  if  A  in  one  min- 
ute, and  B  in  two  minutes,  run  over  10O 
yards,  the  velocity  of  A  will  be  to  that 
"of  B  as  2  to  1 . 

It  appears,  as  far  as  human  obervation 
reaches,  to  be  a  settled  law  of  nature, 
that  u  all  bodies  have  a  tendency,  attrac- 
tion, or  gravitation  towards  one  another." 

The  same  force  applied  to  two  differ- 
ent bodies,  produces  always  the  same 
quantity  of  motion  in  each  of  them.  For 
instance,  let  a  boat,  which  with  its  lad- 
ing is  one  tun,  be  tied  at  a  distance,  to 
another  vessel,  which  with  its  lading  is 
twenty-six  tuns  ;  if  the  rope  that  ties 
tliem  together  be  pulled  either  in  the  less 
or  bigger  of  these  vessels,  the 


Matter  and  Motion.  15 

two,  in  their  approach  one  to  another, 
ivijl  move  twenty-six  foot,  while  the  oth- 
er moves  but  one  foot. 

Wherefore  the  quantity  of  matter  in 
the  earth  being  twenty-six  times  more 
than  in  the  moon,  the  motion  in  the  moon 
towards  the  earth,  by  the  common  force 
of  attraction,  by  which  they  are  impelled 
towards  one  another,  will  be  twenty-six 
times  as  fast  as  in  the  earth  ;  that  is,  the 
moon  will  move  twenty-six  miles  towards 
the  earth,  for  every  mile  the  earth  moves 
towards  the  moon. 

This  attraction  is  the  strongest,  the 
nearer  the  attracting  bodies  are  to  each 
other ;  and  in  different  distances  of  the 
same  bodies,  is  reciprocally  in  the  dupli- 
cate proportion  of  those  distances.  For 
instance,  if  two  bodies,  at  a  given  dis- 
tance, attract  each  other  with  a  certain 
force,  at  half  the  distance,  they  will  at- 
tract each  other  with  four  times  that 
force  ;  at  one  third  of  the  distance,  with 
nine  times  that  force  ;  and  so  on. 

Two  bodies,  at  a  distance,  will  put  one 
•another  into  motion  by  the  force  of  at- 
traction ;  which  is  inexplicable  by  us, 
though  made  evident  to  us  by  experience, 


16  Matter  and  Motion* 

and  so  to  be  taken  as  a  principle  in  na* 
tural  philosophy. 

Supposing  then  the  earth  the  sole  bo- 
dy  in  the  universe,  and  at  rest ;  if  God 
should  create  the  ir.oon,  at  the  same  dis- 
tance that  it  is  now  from  the  earth,  the 
earth  and  the  moon  would  presently  be- 
gin to  move  one  towards  another  in  a 
straight  line,  by  this  motion  of  attraction 
or  gravitation. 

If  a  body,  that  by  the  attraction  of 
another  would  move  in  a  straight  line 
towards  it,  receives  a  new  motion  any 
ways  oblique  to  the  first,  it  will  no  longer 
move  in  a  straight  line,  according  to  ei- 
ther of  those  directions,  but  in  a  curve, 
that  will  partake  of  both  ;  and  this  curve 
will  differ,  according  to  the  nature  and 
quantity  of  the  forces  that  concurred  to 
produce  it;  as,  for  instance,  in  many  ca- 
ses it  will  be  such  a  curve  as  ends  when* 
it  began,  or  recurs  into  itself;  that  is, 
make  up  a  circle,  or  an  ellipsis,  or  oval 
very  little  differing  from  a  circle. 

Attraction  may  be  divided,  with  res- 
pect to  the  law  it  observes, into  two  kinds. 
That  which  takes  place  at  a  sensible,  dis- 
tance^ and  that  which  does  not  extend  to 


Matter  and  Motion*  1 7 

sensible  distances.  The  first  is  called 
the  attraction  of  gravity,  or,  by  mathe- 
maticians, the  centripetal  force. 

This  is  the  species  of  attraction  whose 
laws  we  have  endeavoured  to  elucidate. 
It  is  one  of  the  most  universal  principles 
In  nature.  We  see  and  feel  it  operate  in 
bodies  near  the  earth,  and  find  by  obser- 
vation that  the  same  power  (i.  e.  a  power 
which  acts  in  the  same  manner,  and  by 
the  same  rules,  viz.  always  proportionally 
to  the  quantities  of  mattter,  and  inverse- 
ly as  the  squares  of  the  distances)  does  al- 
so obtain  in  the  moon,  and  the  other  plan- 
ets, both  primary  and  secondary,  as  well 
as  in  the  comets  ;  and  even  that  this  is 
the  very  power  by  which  they  are  all  re- 
tained in  their  orbits.  This  mighty  prin- 
ciple fornixS  the  earth  into  a  round  and 
dense  ball,  holds  every  thing  animate  and 
inanimate  to  its  surface,  and  makes  its 
whole  surface  its  general  top. 

.From  this  attraction  arises  all  the  mo- 
tion, and  consequently  all  the  mutation, 
in  the  great  world.  By  this  heavy  bodies 
descend,  and  light  ones  ascend ;  by  this 
projectiles  are  directed,  vapours  and  ex- 
halations rise,  and  rains  fall  -,  by  this 
B 


1 8  Matter  and  Motion. 

rivers  glide,  the  ocean  swells,  the  air 
presses,  &c. 

2d.  That  which  does  not  extend  to 
sensible  distances.  Such  is  found  to  ob- 
tain in  the  minute  particles  of  which 
bodies  are  composed,  attracting  each  oth- 
er at  or  extremely  near  the  point  of  con- 
tact, with  forces  often  much  superior  to 
that  of  gravity,  but  which  at  any  distance 
decrease  much  faster  than  the  power  of 
gravity.  This  power  a  late  ingenious 
author  calls  the  attraction  of  cohesion, 
as  being  that  by  which  the  atoms  or  in- 
sensible particles  of  bodies  are  united  into 
sensible  masses. 

The  laws  of  motion,  percussion,  &c* 
in  sensible  bodies,  under  various  circum- 
stances, as  falling,  projected,  &c.  do  not 
reach  those  more  recluse  intestine  mo- 
tions in  the  component  particles  of  the 
same  bodies,  on  which  depend  the  chan- 
ges in  the  texture,  colour,  properties,. 
&c.  of  bodies.  So  that  our  philosophy, 
if  it  were  only  founded  on  the  principle 
of  gravitation,  and  even  carried  as  far  as 
this  would  kad  us,  would  still  be  very 
deficient.  But,  besides  the  common  law* 
of  sensible  masses,  the  minute  parts  they 


Matter  and  Motion.  19 

are  composed  of  are  found  subject  to 
some  others,  which  have  but  lately  been 
noticed,,  and  are  even  yet  imperfectly 
known8  Newton  himself,  to  whose  hap- 
py penetration  we  owe  the  hint,  limits 
liimself  with  establishing  that  there  are 
such  motions  in  the  minima  natures,  and 
that  they  flow  from  certain  powers  or 
forces,  not  reducible  to  any  of  those  in 
the  great  world,  and  from  hence  he  ac- 
counts for  an  infinity  of  phenomena,  oth- 
erwise inexplicable,  to  which  the  princi- 
ple of  gravity  is  inadequate.  Thus,  adds 
Sir  Isaac,  "will  nature  be  found  very 
conformable  to  herself,  and  very  simple; 
performing  all  the  great  motions  of  the 
heavenly  bodies  by  the  attraction  of  grav- 
ity, which  intercedes  those  bodies,  and 
almost  all  the  small  ones  of  their  parts, 
by  some  other  attractive  power  diffused 
through  their  particles.  Without  such 
principles,  there  never  would  have  been 
any  motion  in  the  world  ;  and  without 
the  continuance  of  it,  motion  would  soon 
perish,  there  being  otherwise  a  great  de- 
crease or  diminution,  of  it,  which  is  only 
supplied  by  these  active  principles." 
By  the  attraction  of  cohesion  are  form- 


2O  liter  and  Motion. 

cd  stones,  metals,  woods,  salts,  and  eve- 
ry thing  that  may  be  denominated  body. 
The  effects  of  solders,  glue,  cements,  &c. 
are  all  from  the  same  cause.  So  jewels, 
hard  stones,  stalactites,  petrifactions,  por- 
celain, pottery,  bricks,  flags,  glass,  ce- 
ments, artificial  stones,  and  plastic  earthy 
compositions,  which  preserve  their  figure 
in  drying,  all  are  children  of  this  great 
agent ;  and  as  this  power  is  much  great- 
er in  some  bodies  than  in  others,  there 
arises  an  infinite  variety  in  the  strength, 
the  weight,  the  texture,  &c.  of  metals, 
stones,  &c.  for  we  have  powerful  reasons 
to  believe  that  the  original  particles  of  all 
matter  are  of  the  same  weight ;  and  that 
it  is  this  principle  that  makes  thegreat  dif- 
ference in  their  specific  weight.  To  minds 
not  used  to  philosophical  investigation,  it 
must  appear  a  bold  assertion  to  say,  that 
the  particles  of  gold  are  not  one  whit  hea- 
vier than  the  particles  of  cork  ;  but  expe- 
riment and  observation  shew  this  to  be 
really  the  case. 

The  grand  antagonist  principle  of  the 
attraction  of  cohesion  is  fire  (or  caloric 
in  the  new  language  of  chemistry.)  These 
two  opposing  powers  keep  nature  in  a  state 


Matter  and  Motion.  21 

«f  perpetual  motion.  When  the  attractive 
force  is  strongest,  the  body  continues  in  a 
state  of  solidity  ;  but  if,  on  the  contrary, 
heat  has  so  far  removed  the  particles  of  it, 
as  to  place  them  beyond  the  sphere  of  at- 
traction they  lose  their  adhesion,  and  the 
body  becomes  fluid.  Water,  when  cooled 
below  32  degrees  of  Fahrenheit's  ther- 
mometer, becomes  solid,  and  is  called 
ice.  Above  that  temperature,  its  parti- 
cles not  being  held  together,  it  becomes 
liquid  ;  but  when  raised  to  212  degrees, 
its  particles  give  way  to  the  repulsive 
power  of  fire,  and,  flying  off,  assume  an 
aeriform  state,  called  steam  ;  the  same 
may  be  affirmed  of  all  bodies  in  nature, 
for  even  diamonds,  the  hardest  substance 
we  know,  are  capable  of  being  dispersed 
by  a  common  culinary  fire* 

It  may  therefore  be  considered  as  an 
axiom,  that  all  bodies  are  capable  in  cer- 
tain circumstances,  of  the  three  states  of 
!$gtidity\  fluidity^  and  gas. 

The  atoms  of  which  bodies  are  formed, 
are  concealed  from  us  by  their  minute- 
ness, and  though  they  are  the  active  parts 
of  matter,  and  the  great  instruments  of 
Bature,on  which  depend  all  its  operations* 
B2 


32  Matter  and  Motion. 

we  can  form  no  idea  of  them,  for  whether 
we  view  animate  or  inanimate  matter, 
the  corpuscles  of  which  it  is  formed  ^re 
so  infinitely  small,  as  not  only  to  escape 
the  scrutiny  of  the  highest  magnifying 
powers  in  glasses,  but  even  imagination 
itself  is  incapable  of  forming  an  idea  of 
an  original  particle  of  matter :  One  pound 
of  gold  is  capable  of  covering  a  wire  that 
will  circumscribe  the  globe,  nay,  so  infi- 
nite is  this  divisibility  that  Lewenhoeck 
discovered  more  living  animalcules  in  the 
milt  of  on^  single  cod-fish  than  there  are 
jnen,  women,  and  children  on  the  face  of 
the  earth  !  and  those  so  small  that  many 
thousands  may  stand  upon  the  point  of  a 
needle.  And  if  we  suppose  that  these 
animalculae  are  furnished  with  blood,  like 
other  animals,  and  if  the  globules  of  their 
blood  bear  the  same  proportion  to  their 
bulk  as  those  of  a  man  bear  to  his  body,  it 
may  be  proved,  that  the  smallest  visible 
grain  of  sand  would  contain  more  of  these 
globules  than  10,256  of  the  largest  moun- 
tains in  the  world  would  contain  grains 
of  sand. 

When  we    consider   these  tilings  we 
seem  to  look  down  into  infinity  j  and  as. 


Matter  and  Motion.  23 

in  the  contemplation  of  the  starry  heavens, 
we  can  conceive  no  term  to  the  extension 
of  space  ;  so,  in  regarding  the  minute 
parts  of  creation  we  see  no  end  to  the 
divisibility  of  matter.  We  are  lost  in 
wonder  when  we  attempt  to  comprehend 
either  the  vastness  or  the  minuteness  of 
creation,  and  are  necessarily  made  to 
feel  that  it  belongs  only  to  the  one  great 
and  incomprehensible  Power,  who  work- 
eth  in  ways  past  finding  out. 


24  The  Universe* 

CHAP.  II. 

Of  the  Universe. 

TO  any  one,  who  looks  about  him  in 
the  world,  there  at:e  obvious  several  dis- 
tinct masses  of  matter,  separate  from  one 
another  ;  some  whereof  have  discernable 
motions.  These  are  the  sun,  the  fixed 
stars, the  comets,  and  the  planets,  amongst 
which  this  earth,  which  we  inhabit,  is 
one.  All  these  are  visible  to  our  naked 
eyes. 

Besides  these,  telescopes  have  discov« 
ered  several  fixed  stars,  invisible  to  the 
naked  eye  ;  and  several  other  bodies  mo- 
ving about  some  of  the  planets  ;  all  which 
were  invisible  and  unknown,  before  the 
use  of  prospective  glasses  was  found. 

The  vast  distances  between  these  great 
bodies,  are  called  intermundane  spaces  ; 
in  which  though  there  maybe  some  fluid 
matter,  yet  it  is  so  thin  and  subtile  ;  and 
there  is  so  little  of  that  in  respect  of  the 


The  Universe.  i25 

great  masses  that  move  m  those  spaces, 
that  it  is  as  much  as  nothing. 

These  masses  of  matter  are,  either  lu- 
minous, or  opaque  or  dark. 

Luminous  bodies,  are  such  as  give 
light  of  themselves  ;  and  such  are  the 
sun,  and  the  fixed  stars. 

Dark  or  opaque  bodies,  are  such  as 
emit  no  light  of  themselves,  though  they 
are  capable  of  reflecting  it,  when  it  is 
cast  upon  them  from  other  bodies  :  and 
such  are  the  planets. 

There  are  some  opaque  bodies,  as  for 
instance  the  comets,  which  besides  the 
light,  that  they  may  have  from  the  sun, 
seem  to  shine  with  a  "light  that  is  nothing 
else  but  an  accension,  which  they  receive 
from  the  sun,  in  their  near  approaches  to 
It,  in  their  respective  revolutions. 

The  fixed  stars  are  so  called,  because; 
they  always  keep  the  same  distance  one 
from  another. 

On  a  view  of  the  visible  system  of  na- 
ture, by  us  called  the  universe,  the  grand- 
est and  most  admired  object  is  the  great 
luminary  of  day.  Its  splendour,  its  heat, 
its  beneficial  influence  have  always 


26  The  Universe. 

excited  the  particular  attention  of  the  hu- 
man species,  and  have  obtained  the  ado- 
ration of  all  those  nations  which  have  not 
been  blessed  with  revelation. 

Those  who  are  not  accustomed  to  as- 
tronomical calculation,  will  be  surprized 
at  the  real  magnitude  of  this  luminary ; 
\vhich,  on  account  of  its  distance  from  us, 
appears  to  the  eye  not  much  larger  than 
the  moon,  which  is  only  an  attendant  on 
our  earth.  When  looking  at  the  sun, 
we  are  viewing  a  globe,  whose  diameter 
is  890,000  English  miles  ;  whereas  the 
earth  is  no  more  in  diameter  than  7,97O 
miles  :  so  that  the  sun  is  about  1,392,500 
times  bigger  than  the  earth.  Thus  as  it 
is  the  fountain  of  light  and  heat  to  all  the 
planets,  so  it  also  far  surpasses  them  in 
its  bulk. 

.  The  sun  has  several  spots,  which  are 
visible  on  its  surface.  These  spots  were 
entirely  unknown  before  the  invention  of 
telescopes,  though  they  are  sometimes 
of  sufficient  magnitude  to  be  discerned  by 
the  naked  eye.  There  is  a  great  variety 
in  their  magnitudes  ;  some  have  been  so 
large,  as  by  computation  to  be  capable  of 
covering  the  continents  of  Asia  and  Af* 


The  Universe.  27 

rica  ;  nay,  the  whole  surface  of  the  earth, 
or  even  five  times  its  surface. 

The  nature  and  formation  of  the  solar 
spots  have  been  the  subject  of  much 
speculation  and  conjecture.  The  latest 
observations  on  them,  and  on  the  nature 
and  construction  of  the  sun,  are  those  of 
Dr.  Herschel :  he  considers  the  sun  as 
a  most  magnificent  habitable  globe,  sur- 
rounded by  a  double  set  of  clouds.  Those 
which  are  nearest  its  opaque  body,  are 
less  bright,  and  more  closely  connected 
together  than  those  of  the  upper  stratum, 
which  form  the  luminous  apparent  globe 
nve  behold.  This  luminous  external  mat- 
ter is  of  a  phosphoric  nature,  havingseve- 
ral  accidental  openings  in  it,  through 
V/hich  we  see  the  sun's  body,  or  the  more 
opaque  clouds  beneath.  Those  openings 
form  the  spots  we  see. 

Next  to  the  sun,  the  moon  is  the  most 
splendid  and  shining  globe  in  the  hea* 
%-ens  ;  and  by  dissipating,  in  seme  meas- 
ure, the  darkness  and  the  horrors  of  the 
night  ;  subdividing  the  year  into  months, 
and  regulating  the  flux  and  reflux  of  the 
sea,  she  not  only  becojnes  a  pleasing,  but 


28  The  Universes 

a  welcome  object  ;  affording  much  for 
speculation  to  the  contemplative  mind, 
and  of  real  use  to  the  navigator,  the 
traveller,  and  the  husbandman.  The 
Hebrews,  the  Greeks,  the  Romans,  and  in 
general,  all  the  ancients,  used  to  assem- 
ble at  the  time  of  the  new  moon,  to  dis- 
charge the  duties  of  piety  and  gratitude 
for  its  manifold  uses. 

When  we  view  this  attendant  on  our 
earth  in  its  nightly  course,  we  seldom 
form  an  adequate  idea  either  of  its  mag- 
nitude, or  its  motion.  While  it  seems  to 
take  some  hours  in  getting  half  a  yard 
from  a  star  which  it  touched,  we  never 
reflect  that  this  is  an  immense  mass  of 
matter,  of  218O  miles  in  diameter,  dri- 
ving through  the  heavens  at  the  rate  of 
considerably  more  than  two  thousand 
miles  an  hour,  which  is  more  than  double 
of  that  with  which  a  ball  is  shot  off  from 
the  mouth  of  a  cannon. 

The  face  of  the  moon  is  greatly  diver- 
sified with  inequalities,  and  parts  of  dif- 
ferent colours,  some  brighter,  and  some 
darker  than  the  other  parts  of  her  disk. 
When  viewed  through  a  telescope,  her 
face  is  evidently  diversified  with  hills  and 
valleys  :  and  the  same  is  also  shewn  by 


The  Universe.  .29 

the  edge  or  border  of  the  moon  appearing 
jagged,  when  so  viewed,  especially  about 
the  confines  of  the  illuminated  part  when, 
the  moon  is  either  horned  or  gibbous. 

M.  Schroeter,  of  the  Royal  Society  o£ 
Gottingen,  in  the  year  1792,  seems  to  have 
taken  great  pains  to  investigate  the  truth 
of  this  matter,  i  According  to  him,  the 
surface  of  the  moon  appears  to  be  much 
more  unequal  than  that  of  our  earth  ;  and 
these  inequalities  have  great  variety  both 
in  form  and  magnitude.  There  are  large 
irregular  plains,  on  which  are  observed 
long  and  narrow  strata  of  hiljis  running  in 
a  serpentine  direction :  some  of  the  moun- 
tains form  extensive  chains ;  others,  which 
are  in  general  the  highest,  stand  alone, 
and  are  of  a  conical  shape  :  some  have 
craters  ;  others  form  a  circular  ring  in- 
closing a  plain.  The  most  lofty  moun- 
tain on  the  surface  of  our  globe  is  suppo- 
sed to  be  Chimboraco,  which  is  not  twen- 
ty thousand  feet  in  height :  but  there  are 
many  in  the  moon  which  are  much  high- 
er ;  that  which  is  distinguished  by  the 
name  of  Leibnitz^  is  not  less  than  253OOO 
feet. 

C 


30'  The  Universe. 

The  craters  of  the  moon  are  circular, 
and  surrounded  with  an  annular  bank  of 
hills  :  they  are  remarkable  for  their 
width,  many  of  them  being  from  four  to 
fifteen  geographical  miles  in  diameter  : 
some  are  not  deeper  than  the  level  of  the 
moon's  surface  ;  others  are  9000,  12,000, 
and  15,000  feet  in  depth  ;  that  of  one 
which  M.  Schroeter  calls  Bernoiiilli,  is 
above  18,000  feet. 

On  the  face  of  the  moon  are  likewise 
volcanoes  \vhich  appear  to  the  observer 
as  lighted  coals,  and  illuminate  the  neigh- 
bouring mountains. 

With  respect  to  the  nature  and  con- 
'  struction  of  the  moon  and  the  probability 
of  its  being  inhabited,  Dr.  Herschel,  in 
his  papers  published  in  the  Philosophical 
Transactions  of  1795,  concludes,  after 
tracing  the  great  similarity  between  it  and 
the  earth,  as  follows  :  u  There  seems  on- 
ly to  be  wanting,  in  order  to  complete 
the  analogy,  that  it  should  be  inhabited.- 
To  this  it  may  be  objected,  that  we  per- 
ceive no  large  seas  in  the  moon  ;  that  its 
atmosphere  (the  existence  of  which  has 
even  been  doubted  by  many)  is  extreme- 
ly rare,  and  unfit  for  the  purposes  of  ani* 


'The  Universe*  31 

mal  life  ;  that  its  climates,  its  seasons, 
and  the  length  of  its  days,  totally  differ 
from  ours  ;  that  without  dense  clouds 
(which  the  moon  has  not)  there  can  be 
no  rain  ;  perhaps  no  rivers,  no  lakes.  In 
short,  thatr  notwithstanding  the  similarity 
which  has  been  pointed  out,  there  seems 
to  be  a  decided  difference  in  the  two  pla- 
nets we  have  compared.  My  answer  to 
this  will  be,  that  that  very  difference 
which  is  now  objected  will  rather  strength- 
en the  force  of  my  argument  than  lessen 
its  value  ;  we  find,  even  upon  our  globe, 
that  there  is  the  most  striking  difference 
in  the  situation  of  the  creatures  that  live 
upon  it.  While  man  walks  upon  the 
ground,  the  birds  fly  in  the  air,  and  fishes 
.swim  in  water ;  we  can  certainly  not  ob- 
ject to  the  conveniences  afforded  by  the 
moon,  if  those  that  are  to  inhabit  its  re- 
gions are  fitted  to  their  conditions  as  well 
as  we  on  this  globe  are  to  ours.  An  ab- 
solute or  total  sameness  seerns  rather  to 
denote  imperfections,  such  as  nature  ne- 
ver exposes  to  our  view  ;  and,  on  this  ac- 
count, I  believe  the  analogies  that  have 
been  mentioned  fully  sufficient  to  estab- 
lish the  high  probability  of  the  moon's 
being  inhabited  like  the  earth." 


32  The  Universe. 

— Lastly  of  the  earth  on  which  we  dwell, 
Speck  as  this  may  appear  in  the  im- 
mensity of  creation,  it  is  nevertheless  to 
us  of  the  highest  importance;  we  only 
wish  to  obtain  a  knowledge  of  other  pla- 
ne ts%and  systems,  that  we  may  find  out 
their  relation  to  this,  and  from  thence 
learn  our  connection  with  the  universe  at 
large. 

The  external  part  of  the  earth  either 
exhibits  inequalities,  as  mountains  and 
valleys  ;  or  it  is  plane  and  level ;  or  dug 
in  channels,  fissures,  beds,  &c.  for  rivers, 
lakes,  seas,  &c. — These  inequalities  in 
the  face  of  the  globe  most  naturalists 
suppose  have  arisen  from  a  rupture  or 
subversion  of  the  earth,  by  the  force  ei- 
ther of  the  subterraneous  fires  or  waters. 
The  earth  in  its  natural  and  original  state, 
It  has  been  supposed  by  Des  Cartes,  and 
after  him  Burnet,  Steno,  Woodward, 
Whiston  and  others,  was  perfectly  round, 
smooth,  and  equable  ;  and  they  account 
for  its  present  rude  and  irregular  form, 
principally  from  the  great  deluge  ;  but 
from  whatever  cause  those  inequalities 
may  have  arose,  or  at  what  period,  they 
seem  a  necessary  part  of  the  econonr 


The  Universe*  SS 

nature.  It  is  the  intermediate  space  be- 
tween the  mountain's  top  and  the  sea- 
shore that  forms  the  habitation  of  plants 
and  animals. — While  there  is  sea-shore 
and  high  ground,  there  is  that  which  is 
required  in  the  system  of  the  world  ; 
take  that  away,  and  there  would  remain 
an  aqueous  globe  in  which  the  world 
would  perish. 

What  the  internal  or  central  part  of  the 
earth  is  composed  of  is  utterly  unknown 
to  us,  though  many  opinions  have  been 
formed  respecting  it ;  the  utmost  depth  to 
which  it  hath  been  penetrated  by  human 
art  not  being  more  than  2400  feet,  or  less 
than  half  a  mile,  which,  when  compared 
with  the  length  of  the  diameter,  is  a  very 
-short  distance  indeed..  From  its  mean 
density,  however,  which  is  to  that  of  wa- 
ter as  9  to  2,  and  to  common  stone  as  9 
to  5,  it  is  presumed  that  it  contains  great 
quantities  of  metals. 

The  figure  of  the  earth  is  that  of  a 
spheroid,  having  its  equatorial  diameter 
longer  than  its  polar  diameter.  It  is  con- 
sequently flattest  at  the  poles,  and  more 
protuberant  at  the  equator. 

With  respect  to  the  magnitude  of  the 
C2 


34  The  Universe. 

earth,  this  has  been  variously  determined 
by  different  authors,  both  ancient  and 
modern. — The  following  dimensions  may 
be  taken  as  near  the  truth. 

The  circumference  .  .  25,OOO  miles. 
The  polar  diameter    .    .  7893  miles, 
The  equatorial  diameter  7928  miles, 
The  superficies  198,944,206  sq.  miles. 
The  solidity  263,930,000,000  cubic  m. 
Also  the  seas,  and  unknown  parts  of  the 
earth,  by  a  measurement  of  the  best  maps, 
contain  160,522,026  square  miles  ;  the  in- 
habited parts,  38,922,180  ;  of  which  Eu- 
rope contains  4,456,065  ;   Asia,  10,768,- 
823  ;   Africa,  9,654,807  ;  and   America, 
14,110,874  square  miles. 

Of  the  divisions  of  the  Earth. — In  tak- 
ing a  view  of  the  terraqueous  globe  the 
3iiost  obvious  divisions  that  present  them- 
selves, are  those  that  are  sketched  by  the 
yielding  water  on  the  crooked  shore,  call- 
ed continents,  islands,  seas,  &c. 

A  continent  is  a  large  tract  of  land  not 
separated  by  the  sea ;  as  Europe,  Asia, 
&c.  An  ocean  is  a  vast  collection  of  wa- 
ter not  separated  by  land  ;  as  the  Atlan- 
tic, Pacific,  &c. — A  sea  is  a  smaller  col- 
lection of  water  communicating  with  the 


The  Universe.  35 

ocean  ;  as  the  Mediterranean,  the  Baltic. 

An  island  is  a  tract  of  land  surrounded 
by  water;  as  Great  Britain,  Ireland,  &cc. 
A  lake  is  water  surrounded  by  land  ;  as 
the  Lake  of  Geneva. 

A  cape  or  promontory  is  a  point  of  land 
running  far  into  the  sea ;  as  the  Cape  of 
Good  Hope.  A  bay  is  a  part  of  the 
ocean  running  far  into  the  land  j  as  the 
Bay  of  Biscay. 

A  peninsula  is  land  almost  surrounded 
with  water  ;  as  the  Morea.  A  gulph  is 
a  part  of  the  sea  almost  surrounded  with 
land  ;  as  the  Gulph  of  Venice. 

An  isthmus  is  the  narrow  part  of  land 
which  joins  the  peninsula  to  any  country  ; 
as  the  Isthmus  of  Suez.  A  Strait  is  a  nar- 
row passage  from  one  sea  to  another  ;  as 
the  Strait  of  Gibraltar. 

The  earth  is  also  divided  into  four  quar- 
ters ;  Europe,  Asia,  Africa,  and  America. 

Besides  these,  there  are  other  divi- 
sions of  a  more  varying  character  ;  such 
are  the  political  boundaries  that  separate 
kingdoms  and  empires. 

Kingdoms,  provinces,  towns,  &c.  are 
divisions  of  the  earth  that  change  with  th$ 


36  The  Universe, 

affairs  of  the  nations  that  have  made 
them  ;  and  accordingly  in  different  ages? 
:they  alter  their  appearances. 


Solar  System* 


CHAP.  III. 

Of  the  Solar  System. 

OUR  solar  system  consists  of  the  sun, 
and  the  planets,  and  comets  moving  about 
it. 

The  planets  are  bodies  which  appear 
to  us  like  stars  ;  not  that  they  are  lumi- 
nous bodies,  that  is,  have  light  in  them- 
selves ;  but  they  shine  by  reflecting  the 
sun. 

They  are  called  planets  from  a  Greek 
word,  which  signifies  wandering ;  be- 
cause they  change  their  places,  and  do 
not  always  keep  the  same  distance  with 
one  another,  nor  with  the  fixed  stars,  as 
the  fixed  stars  do. 

There  are  two  kinds  of  planets,  prima- 
ry and  secondary.  The  first  move  round 
the  sun,  and  respect  him  only  as  the  cen- 
ter of  their  motions.  The  secondary 
planets,  called  also  satellites,  or  moons, 
are  smaller  planets,  revolving  round  the 


S3  Solar  System. 

primary,  while  they,  with  the  primary 
planets  about  which  they  move,  are  car- 
ried round  the  sun.  The  planets  move 
round  the  sun  at  various  distances,  some 
being  much  nearer  to  him  than  our  earth, 
and  others  being  much  further  off. 

There  are  nine  primary  planets,  which 
are  situated  with  respect  to  their  distan- 
ces from  the  sun  as  follows  : 

?  ?  ©  <? 

Mercury,     Venus,    The  Earth,  Mars,  Ceres,  Pallas  t 

2f   "       T?  $ 

Jupiter,  Saturn,  and  Herschel,  or  the  Georgium  Sidus. 

Of  these,  our  earth  is  accompanied  by 
one  moon,  Jupiter  has  four  moons,  Sa- 
turn has  seven  moons,  and  the  Georgium, 
planet  has  six  moons.  None  of  these 
moons,  except  our  own,  can  be  seen  with- 
out a  good  telescope.  The  other  five 
planets  do  not  appear  to  have  any  satel- 
lites or  moons. 

All  the  planets  move  round  the  sun 
from  west  to  east,  and  in  the  same  direc- 
tion do  the  moons  revolve  round  their 
primaries,  excepting  thos^  of  the  Georgi- 
um planet,  which  seem  to  move  in  a  con- 
trary direction.  The  paths  in  which 
they  move  round  are  called  their  orbits* 


Solar  System.  *      3$ 

They  perform  their  revolutions  also  in 
very  different  periods  of  time.  The  time 
of  performing  their  revolutions  round 
the  sun  is  called  their  year,  and  the  time 
of  performing  their  revolutions  on  their 
axes  their  daij. 

The  axis  of  a  planet  is  an  imaginary 
line  conceived  to  be  drawn  through  its 
center,  about  which  it  revolves  as  if  on  a 
real  axis.  The  extremities  of  this  linet 
terminating  in  opposite  points  of  the 
planet's  surface  are  called  its  poles.  A 
bowl  whirled  from  one's  hand  into  the 
open  air  turns  round  such  a  line  with- 
in itself,  whilst  it  moves  forward;  and 
such  are  the  lines  we  mean  when  we 
speak  of  the  axes  of  the  heavenly  bodies, 

Venus  and  Mercury  being  nearer  to 
the  sun  than  our  earth,  are  called  inferior 
planets,  and  all  the  rest,  which  are  with- 
out the  earth's  orbit,  are  called  superior 
planets. 

The  sun  is  placed  near  the  common 
center,  or  rather  in  the  lower*  focus  of 

*  If  a  thread  be  tied  loosely  round  two  pins 
stuck  in  a  table,  and  moderately  stretched  by  the 
point  of  a  black-lead  pencil  carried  round  by  an 
even  motion  and  light  pressure  of  the  hand,  an 


40  Solar  System* 

the  orbits  of  all  the  planets  and  comets, 
and  turns  round  his  axis  in  25  days  6 
hours,  as  is  evident  by  the  motion  of 
spots  seen  on  his  surface.  By  the  vari- 
ous attractions  of  the  circumvolving  plan- 
ets, he  is  agitated  by  a  small  motion 
round  the  center  of  gravity  of  the  system. 
Let  us  suppose  the  earth's  orbit  to  be 
a  thin,  even,  solid  plane  ;  cutting  the  sun 
through  the  center,  and  extended  out  as 
far  as  the  starry  heavens,  where  it  will 
mark  the  great  circle  called  the  Ecliptic. 
This  circle  we  suppose  to  be  divided  into 
12  equal  parts,  called  Signs  ;  each  sign 
into  30  equal  parts,  called  Degrees  ;  each 
degree  into  6O  equal  parts  called  Minutes  ; 
and  every  minute  into  GO  equal  parts, 
called  Seconds ;  so  that  a  second  is  the 
60th  part  of  a  minute  ;  a  minute  the  60th 
part  of  a  degree  ;  and  a  degree  the  360th 
part  of  a  circle,  or  30th  part  of  a  Sign. 
The  ^lanes  of  the  orbits  of  all  the  other 

ova!  ellipsis  will  be  described ;  the  two  points 
where  the  pins  are  fixed  being1  called  the  foci  or 
focuses  thereof.  The  orbits  of  all  the  planets  are 
elliptical,  and  the  sun  is  placed  in  or  near  one  of 
the  foci  of  each  of  them  ;  and  that  in  which  he  is 
placed  is  called  the  lower  focus. 


Solar  System*  41 

planets  likewise  cut  the  sun  in  halves  ; 
but  extended  to  the  heavens,  form  circles 
different  from  one  another,  and  from  the 
ecliptic  ;  one  half  of  each  being  on  the 
north  side,  and  the  other  on  the  south 
side  of  it.  Consequently  the  orbit  of 
each  planet  crosses  the  ecliptic  in  two  op- 
posite points,  which  are  called  the  plan- 
et's Nodes. 

Mercury  is  the  first  planet  in  the  or- 
der of  the  system.  It  is  computed  to  be 
about  37,000,000  miles  distant  from  the 
sun,  and  to  move  at  the  rate  of  105,000 
miles  an  hour,  completing  its  orbit  in 
about  88  of  our  days,  or  little  less  than 
three  months,  which  is  the  length  of  its 
year.  It  is  not  much  larger  than  the 
moon,  being  about  3200  miles  in  diame- 
ter. 

Venus  is  the  second  planet  from  the 
sun,  remarkable  for  its  brightness,  it  is 
computed  to  be  68,000,000  miles  from 
it,  and  to  move  round  it  at  the  rate  of 
76,000  miles  an  hour,  completing  its 
annual  revolution  in  224  days  17  hours, 
or  above  7£  months.  Its  diameter  is 
7700  miles,  and  its  diurnal  revolution  is 
performed  in  23  hours  22  minutes. 
D 


42  Solar  System. 

When  it  is  to  the  west  of  the  sun,  it  is 
a  morning  star  ;  when  to  the  east,  it  is  an 
evening  star. 

Our  Earth  is  the  third  planet  in  the 
order  of  our  system.  Its  diameter  is 
7970  miles,  and  it  turns  round  on  its  axis 
in  the  course  of  a  day.  Its  distance  from 
the  sun  is  95,000,000  miles,  and  moves 
at  the  rate  of  58,000  miles  an  hour,  com- 
pleting its  orbit  in  the  course  of  a  year. 

Mars  is  the  fourth  planet  from  the 
sun,  from  which  it  is  distant  about 
144,000,000  miles.  It  moves  at  the  rate 
of  55,000  miles  an  hour,  and  completes 
its  orbit  in  a  little  less  than  two  of  our 
years.  Its  diameter  is  4200  miles,  and 
its  rotation  on  its  axis  is  performed  in 
about  24  hours  and  39  minutes. 

Ceres  Ferdinandea  is  the  fifth  planet 
from  the  sun.  Its  diameter  is  16O 
miles,  and  its  distance  from  the  sun  is 
260,000,000  miles.  It  was  discovered 
on  the  first  day  of  the  present  century  by 
Mr.  Piazzi,  an  Italian  astronomer. 

Pallas  is  the  sixth  planet  in  the  order 
of  the  system.  It  was  discovered  by 
Dr.  Gibers  of  Bremen,  on  the  28ch  of 
March,  1802.  Its  distance  from  the  sun 


Solar  System*  43 

is  266,000,000  miles,  and  its  diameter 
80  miles. 

This  planet  and  the  last  Dr.  Herschel 
proposes  to  call  asteroids,  because  they 
are  so  much  smaller  than  any  of  the  oth- 
er planets. 

Jupiter  is  the  seventh  planet  in  the  or- 
der of  our  system,  and  the  largest  that 
has  yet  been  discovered,  being  nearly  a 
thousand  times  as  large  as  our  earth. 
He  is  computed  to  be  about  490,000,000 
miles  from  the  sun,  to  go  at  the  rate  of 
29,000  miles  an  hour,  and  to  be  89,000 
miles  in  diameter.  He  finishes  his  annu- 
al period  in  eleven  of  our  years  314  days 
and  12  hours,  and  turns  round  his  axis 
in  9  hours  56  minutes ;  so  that  his  year 
contains  10,470  days*  From  this  plan- 
et's turning  so  swiftly  on  its  axis,  its  fi- 
gure is  more  oblate  than  that  of  the  earth, 
being  more  than  six  thousand  miles  long- 
er in  its  equatorial  than  in  its  polar  di- 
ameter ;  this  swiftness  of  its  diurnal  mo- 
tion also  draws  its  clouds  and  vapours 
into  streaks  or  lines  over  its  equatorial 
parts,  forming  what  is  called  Jupiter's 
belts. 

Saturn  is  the  eighth  planet  from  the 


44  Solar  System. 

sun,  and  is  about  900,000,000  miles  dis- 
tant from  it ;  it  is  carried  along  its  orbit 
at  the  rate  of  22,000  miles  an  hour,  which 
it  completes  in  29 l  of  our  years.  Its 
diameter  is  computed  to  be  79,OOO  miles  ; 
its  rotation  on  its  axis  has  been  discover- 
ed by  Herschel  to  be  completed  in  about 
ten  hours  and  a  quarter.  There  is  a  ring, 
or  a  broad  circular  arch,  encompasses 
the  body  of  this  planet,  without  touching 
it,  somewhat  similar  to  the  wooden  hori- 
zon of  an  artificial  globe  ;  only  that  the 
interior  space  occupied  by  the  planet  is 
very  considerable.  It  is  about  21,000 
miles  in  breadth  ;  which  is  equal  to  its 
distance  from  Saturn  on  all  sides.  It 
appears  like  a  large  luminous  arch  in  the 
heavens,  as  if  it  did  not  belong  to  the 
planet. 

Herschel  is  the  ninth  planet  in  the  or- 
der of  our  system,  and  is  twice  as  far  dis- 
tant as  Saturn  from  the  sun,  and  will  be 
nearly  83  years  in  going  round  it.  It 
is  ninety  times  as  large  as  the  earth,  and 
is  visible  to  the  naked  eye  on  a  clear  eve- 
ning, if  the  moon  be  absent. 

Thtrse  with  their  moons  we  consider 
as  the  regular  bodies  of  our  system,  so 


Solar  System*  45 

regular  indeed,  that  their  phenomena 
may  be  pretty  exactly  calculated  for  ages. 
There  may  be  other  planets,  which  hu- 
man observation  has  not  yet  discovered, 
and  which,  perhaps,  it  never  may. 

All  the  planets  move  nearly  in  the  di- 
rection of  the  ecliptic  ;  and  that  space 
on  each  side  of  it,  which  bounds  their  ut- 
most deviations,  is  called  the  Zodiac.  It 
is  a  broad  circle  or  belt  in  the  starry 
heavens  ;  and  is  about  16  degrees  in 
breadth,  and  the  ecliptic  equally  divides 
it  in  two  all  round,  so  that  the  planets  are 
always  found  amongst  some  of  the  con- 
tellations,  which  form  the  twelve  signs  of 
the  zodiac. 

The  reason  of  their  motions  in  curve 
lines,  is  the  attraction  of  the  sun,  or  their 
gravitations  towards  the  sun  (call  it 
which  you  please  ;)  and  an  oblique  or 
side-long  impulse  or  motion  ;  the  former 
is  commonly  called  the  centripetal  force  , 
and  the  latter  the  centrifugal  force. 

These  two  motions  or  tendencies,  the 

one  always  endeavouring  to  carry  them 

ma  straight  line  from  the  circle  they  move 

in,  and  the  other  endeavouring  to  draw 

D2 


46  Solar  System. 

them  in  a  straight  line  to  the  sun,  make 
that  a  curve  line  they  revolve  in. 

From  the  great  analogy  there  is  be- 
tween the  other  planets  and  our  earth  it  is 
generally  supposed  by  astronomers  that 
they  are  inhabited,  and  indeed  we  can 
never  bring  ourselves  to  think,  that  an  in- 
finitely wise  Creator  should  dispose  of 
all  his  animals  and  vegetables  here,  leav- 
ing the  other  magnificent  planets,  with  all 
their  noble  attendance  of  moons,  bare 
and  destitute  of  rational  creatures.  To 
suppose  that  he  had  any  view  to  our  bene- 
fit, in  creating  these  moons,  and  giving 
them  their  motions  round  Jupiter,  Sa- 
turn arid  Herschel;  to  imagine  that  he 
intended  these  vast  bodies  for  any  ad- 
vantage to  us,  when  he  well  knew  that 
they  could  never  be  seen  but  by  a  few 
astronomers  peeping  through  telescopes  : 
and  that  he  gave  to  the  planets  regular 
returns  of  days  and  nights,  and  different 
seasons  to  all  where  they  would  be  con- 
venient ;  but  of  no  manner  of  service  to 
us,  except  only  what  immediately  regards 
our  own  planet  the  earth  ;  to  imagine  that 
he  did  all  this  on  our  account,  would  be 
charging  him  impiously  with  having 


Solar  System.  47 

done  much  in  vain  ;  and  as  absurd,  as  to 
imagine  that  he  has  created  a  little  sun 
and  a  planetary  system  within  the  shell 
of  our  earth,  and  intended  them  for  our 
use.  These  considerations  amount  to 
little  less  than  a  positive  proof,  that  all 
the  planets  are  inhabited ;  for  if  they  are 
not,  why  all  this  care  in  furnishing  them 
with  so  many  moons,  to  supply  those 
with  light  which  are  at  the  greater  dis- 
tances from  the  sun  ?  Do  we  not  see, 
that  the  farther  a  planet  is  from  the  sun, 
the  greater  apparatus  it  has  for  that  pur- 
pose ?  save  only  Mars,  which  being  but 
a  small  planet,  may  have  moons  too  small 
to  be  seen  by  us.  We  know  that  the 
earth  goes  round  the  sun,  and  turns 
round  its  own  axis,  to  produce  the  vicis- 
situdes of  summer  and  winter  by  the 
former,  and  of  day  and  night  by  the  latter 
motion,  for  the  benefit  of  its  inhabitants. 
IVIay  we  not  then  fairly  conclude,  by  pa- 
rity of  reason,  that  the  end  and  design  of 
all  the  other  planets  is  the  same  ?  and  is 
not  this  agreeable  to  the  beautiful  harmo- 
ny which  exists  throughout th^  universe? 
Surely  it  is  ;  and  raises  in  us  the  most 
magnificent  ideas  of  the  Supreme  Being, 


48  Solar  System. 

who  is  everywhere,  and  at  all  times  pre- 
sent ;  displaying  his  power,  wisdom  and 
goodness  among  all  his  creatures !  and 
distributing  happiness  to  innumerable 
ranks  of  various  beings  ! 


Of  Comets. — Of  all  the  celestial  bodies, 
comets  have  given  rise  to  the  greatest 
number  of  speculations  and  conjectures. 
Their  strange  appearance  has  in  all  ages 
been  a  matter  of  terror  to  the  uninform- 
ed, who  have  generally  looked  upon  them 
to  be  evil  omens,  and  forerunners  of  war, 
pestilence,  &c. 

The  existence  of  an  universal  connec- 
tion between  all  parts  of  the  siderial  hea- 
vens is  now  generally  admitted.  Comets 
undoubtedly  form  a  part  of  this  great 
chain  ;  but  of  the  part  they  occupy,  and 
of  the  uses  for  which  they  exist,  we  are 
in  a  great  measure  ignorant.  It  is  a  por- 
tion of  science  whose  perfection  is  reser- 
ved for  some  distant  day,  when  these  bo- 
dies, and  their  vast  orbits,  may,  by  long 
and  accurate  observation,  be  added  to  the 
known  parts  of  the  solar  system  ;  when 
astronomy  will  appear  with  new  lights, 
after  all  our  discoveries,  great  as  we  at 


Solar  System.  49 

present  imagine  them  to  be.  Upon  the 
whole,  the  astronomy  of  comets  is  very 
imperfect ;  for  but  little  can  be  known 
with  certainty  where  but  little  can  be 
seen.  Comets  afford  few  observations, 
on  which  to  ground  conjecture,  and  are 
for  the  greatest  part  of  their  course  be- 
yond the  reach  of  human  vision. 

Like  the  planets,  they  are  observed  to 
be  opaque  bodies,  shining  only  by  the  in- 
fluence of  the  sun,  and  like  them  are  car- 
ried along  in  their  orbits,  by  the  combi- 
nation of  the  centripetal  and  centrifugal 
forces  ;  sometimes  seeming  to  go  for- 
wards, sometimes  backwards,  and  some 
times  to  be  stationary.  The  great  eccen- 
tricity of  their  orbits  make  them  liable  to 
suffer  considerable  alterations,  from  the 
attraction  of  the  planets,  and  of  each  oth- 
er. 

They  are  called  comets,  from  their 
having  a  long  tail,  somewhat  resembling 
the  appearance  of  hair.  This,  however, 
is  not  always  the  case  ;  for  some  comets 
have  appeared,  which  were  as  well  defi- 
ned, and  as  round  as  planets  ;  but  in  gen- 
eral, they  have  luminous  matter  diffused 
around  them,  or  projecting  out  from 
them. 


50  Solar  System. 

From  the  beginning  of  our  era  to  this 
time,  it  is  probable,  according  to  the  best 
accounts,  that  there  have  appeared  about 
500  comets.  Before  that  time  about  10O 
others  are  recorded  to  have  been  seen, 
but  it  is  probable,  that  not  above  half  of 
them  were  comets.  And,  when  we  con- 
sider, that  many  others  may  not  have 
been  perceived,  from  being  too  near  the 
sun,  from  appearing  in  moonlight,  from 
being  in  the  other  hemisphere,  from  be- 
ing too  small  to  be  perceived,  or  which 
may  not  have  been  recorded,  we  might 
imagine  the  whole  number  to  be  consid- 
erablv  greater  :  but  it  is  likely,  that  of  the 
comets  which  are  recorded  to  have  been 
seen,  the  same  may  have  appeared  seve- 
ral times,  and  therefore  the  number  may 
be  less  than  is  here  stated. 


Of  the  Moon. — The  moon  goes  round 
the  earth  from  change  to  change  in  29 
days  12  hours  and  44  minutes  ;  and  round 
the  sun  with  it  every  year.  The  moon's 
diameter  is  2180  miles;  and  her  dis- 
tance from  the  earth's  center  24O,OOO 
miles.  She  goes  round  her  orbit  in  27 
days  7  hours  43  minutes,  moving  about 


Solar  System.  51 

r2290  miles  every  hour  ;  and  turns  round 
her  axis  exactly  in  the  time  that  she  goes 
round  the  earth,  which  is  the  reason  of 
her  keeping  always  the  same  side  towards 
us,  and  that  her  day  and  night  taken  to- 
gether is  as  long  as  our  lunar  month. 

The  moon  is  an  opaque  globe  like  the 
earth,  and  shines  only  by  reflecting  the 
light  of  the  Sun  ;  therefore  whilst  that 
half  of  her  which  is  towards  the  sun  is 
enlightened,  the  other  half  must  be  dark 
and  invisible.  Hence  she  is  incessantly 
varying  her  appearance  ;  sometimes  she 
looks  full  upon  us,  and  her  visage  is  all 
lustre  ;  sometimes  she  shews  only  half 
her  enlightened  face,  soon  she  appears  as 
a  radiant  crescent,  in  a  little  time  all  her 
brightness  vanishes,  and  she  becomes  a 
beamless  orb.  The  full  moon,  or  oppo- 
sition, is  that  state  in  which  her  whole 
disk  is  enlightened,  and  we  see  it  all 
bright,  and  of  a  circular  figure.  The 
new  moon  is  when  she  is  in  conjunction 
with  the  sun  ;  in  this  state,  the  whole 
surface  turned  towards  us  is  dark,  and  is 
therefore  invisible  to  us.  The  first  quar- 
ter of  the  moon  she  appears  in  the  form 
of  a  semicircle,  whose  circumference  is 


52  .  Solar  System. 

turned  towards  the  west.  At  the  last 
quarter  she  appears  again  under  the  form 
of  a  semicircle,  but  with  the  circumfer- 
ence turned  towards  the  east.  These 
phases  may  be  illustrated  in  a  very  plea- 
sing manner,  by  exposing  an  ivory  ball 
to  the  sun,  in  a  variety  of  positions,  by 
which  it  may  present  a  greater  or  small- 
*er  part  of  its  illuminated  surface  to  the 
observer.  If  it  be  held  nearly  in  opposi- 
tion, so  that  the  eye  of  the  observer  be 
almost  immediately  between  it  and  the 
sun,  the  greatest  part  of  th^;  enlightened 
side  will  be  seen  ;  but  if  it  be  moved  in  a 
circular  orbit,  towards  the  sun,  the  visi- 
ble enlightened  pari  will  gradually  de- 
crease, and  at  last  disappear,  when  the 
ball  is  held  directly  towards  the  sun.  Or 
to  apply  the  experiment  more  immedi^ 
ately  to  our  purpose  ;  if  the  ball,  at  any 
time  when  the  sun  and  moon  are  both 
visible,  be  held  directly  between  the  eye 
of  the  observer  and  the  moon,  that  part 
of  the  ball  on  which  the  sun  shines,  will 
appear  exactly  of  the  same  figure  as  the 
moon  itself. 

The  moon  has  scarce  any  difference  of 
seasons  ;  her  axis  being  almost  perpenv 


Solar  System.  53 

dicular  to  the  ecliptic.  What  is  very 
singular,  one  half  of  her  has  no  darkness 
at  all ;  the  earth  constantly  affording  it  a 
strong  light  in  the  sun's  absence  ;  while 
the  other  half  has  a  fortnight's  darkness 
and  a  fortnight's  light  by  turns. 

Our  earth  is  a  moon  to  the  moon,  wax- 
ing and  waning  regularly,  but  appearing 
thirteen  times  as  big,  and  affording  her 
thirteen  times  as  much  light,  as  she  does 
to  us.  When  she  changes  to  us,  the  earth 
appears  full  to  her  ;  and  when  she  is  in 
her  first  quarter  to  us,  the  earth  is  in  its 
third  quarter  to  her  ;  and  v ice  versa. 


Of  Eclipses. — When  any  of  the  hea- 
venly bodies  is  obscured  or  darkened  by 
the  shadow  of  another  falling  upon  it,  or 
by  the  interposition  of  any  body,  it  is  said 
to  be  eclipsed. 

An  eclipse  of  the  moon  is,  when  the 
earth,  being  between  the  sun  and  the 
moon,  hinders  the  light  of  the  sun  from 
falling  upon  and  being  reflected  by  the 
moon.  If  the  light  of  the  sun  is  kept  off 
from  the  whole  body  of  the  moon,  it  is  a 
total  eclipse  j  if  from  a  part  only,  it  is  a 
partial  one. 

E 


y4t  Solar  System. 

An  eclipse  of  the  swi  is,  when  the 
moon,  being  between  the  sun  and  the 
earth,  hinders  the  light  of  the  sun  from 
coming  to  us.  If  the  moon  hides  from, 
us  the  whole  body  of  the  sun,  it  is  a  to- 
tal eclipse,  if  not,  a  partial  one. 

The  eclipses  of  the  sun  and  the  moon, 
though  expressed  by  the  same  word,  are 
in  nature  very  different ;  the  sun,  in  re- 
ality, loses  nothing  of  its  native  lustre  in 
the  greatest  eclipses,  but  is  all  the  while 
incessantly  sending  forth  streams  of  light 
every  way  around  him,  as  copiously  as 
before.  Some  of  these  streams  are,  how- 
ever, intercepted,  in  their  way  towards 
our  earth,  by  the  moon  coming  between 
the  earth  and  the  sun  ;  and  the  moon  ha- 
ving no  light  of  her  own,  and  receiving 
none  from  the  sun  on  that  half  of  the 
globe  which  is  towards  our  eye,  must 
appear  dark,  and  make  so  much  of  the 
sun's  disk  appear  so,  as  is  hid  from  us  by 
her  interposition.  What  is  called  an 
eclipse  of  the  sun,  is  therefore,  in  reality, 
an  eclipse  of  the  earth,  which  is  deprived 
of  the  sun's  light,  by  the  moon's  coming 
between,  and  casting  a  shadow  upon  it. 
The  earth  being  a  globe,  only  that  half 


Solar  System.  55' 

®F  it,  which  at  any  time  is  turned  towards 
the  sun,  can  be  enlightened  by  him  at 
that  time  :  it  is  some  part  of  this  enlight- 
ened half  of  the  earth  that  the  moon's 
shadow  falls  on  in  a  solar  eclipse. 

In  any  year  the  number  of  eclipses  of 
both  luminaries  cannot  be  less  than  two,, 
nor  more  than  six*  Eclipses  of  the  sun 
are  more  frequent  than  of  the  moon,  be- 
cause the  sun's  ecliptic  limits  are  greater 
than  the  moon's  ;  yet  we  have  more  visi- 
ble eclipses  of  the  moon  than  of  the  sun, 
because  eclipses  of  the  moon  are  seen 
from  all  parts  of  that  hemisphere  of  the 
earth  which  isnext  them,  and  are  equally 
great  to  each  of  those  parts  ;  but  the  sun's 
eclipses  are  visible  only  to  that  small 
portion  of  the  hemisphere  where  the 
moon's  shadow  falls. 

An  eclipse  of  the  moon  can  never  hap- 
pen but  at  the  time  of  full  moon. 

An  eclipse  of  the  sun  always  begins  on 
the  western,  and  ends  on  the  eastern  side  ; 
because  the  moon,  moving  in  her  orbit 
from  west  to  east,  necessarily  first  ar- 
rives and  touches  the  sun's  western  limb, 
and  goes  off  at  the  eastern  ;  that  of  the 


5"6  Solar  System. 

moon  commences  at  the  eastern  and  ends 
at  the  western. 

The  Satellites,  or  moons,  are  often 
eclipsed  by  the  planets  to  which  they  be- 
long. 

A  digit  is  the  12th  part  of  the  sun  or 
moon's  diameter,  and  is  a  term  often 
used  in  speaking  of  eclipses.  The  disk 
of  the  sun  or  moon  is  its  round  face, 
which,  on  account  of  the  great  distance 
of  the  object,  appears  fiat.  The  edge  or 
border  of  the  disk  is  called  the  limb. 

The  immersion  of  a  heavenly  body,  is 
the  time  when  an  eclipse  begins  ;  its 
-emersion  is  when  it  begins  to  re-appear. 


Fixed  Stars.  57 


CHAP.  IV. 
Of  the  Fixed  Stars, 

NO  part  of  the  universe  affords  such 
exalted  ideas  of  the  structure  and  mag- 
nificence of  the  heavens,  as  the  consider- 
ation of  the  number,  magnitude,  nature, 
and  distance  of  the  fixed  stars.  We  ad- 
mire indeed,  with  propriety,  the  vast 
bulk  of  our  own  globe  ;  but,  when  we 
consider  how  much  it  is  surpassed  by 
most  of  the  heavenly  bodies,  what  a  point 
it  degenerates  into,  and  how  little  more 
even  the  vast  orbit  in  which  it  revolves 
would  appear,  when  seen  from  some  of 
the  fixed  stars,  we  begin  to  conceive  more 
just  ideas  of  the  extent,  of  the  universe, 
and  of  the  infinity  of  creation. 

The  fixed  stars  comprehend  all  the  ce- 
lestial objects,    excepting   the   sun,   the 
moon,  and  the  planets,  and  some  comets 
which  now  and  then  appear, 
E2 


58  fixed  Star, s. 

The  stars,  on  account  of  their  apparent- 
ly various  magnitudes,have  been  distribu- 
ted into  several  classes  or  orders.  Those 
which  appear  largest,  are  called  stars  of 
the  first  magnitude  ;  the  next  to  them  in 
lustre,  stars  of  the  second  magnitude;  and 
soon  to  the  sixth, which  are  the  smallest 
that  are  visible  to  the  bare  eye.  This 
distribution  having  been  made  long  be- 
fore the  invention  of  telescopes,  the  stars 
which  cannot  be  seen  without  the  assist- 
ance of  these  instruments,  are  distinguish- 
ed by  the  name  of  telescopic  stars. 

They  are  likewise  distinguished,  with 
regard  to  their  situation,  into  asterisms, 
or  constellations  ;  which  are  nothing  but 
assemblages  of  several  neighbouring  stars 
considered  as  constituting  some  deter- 
minate figure,  as  of  an  animal,  &c.  from 
which  it  is  therefore  denominated. 

The  number  of  constellations  in  the 
northern  hemisphere  is  35  ;  in  the  south- 
ern 32  ;  and  in  the  ecliptic  12.  Those 
stars  which  are  not  :  in  the  con- 

stellations, are  called  unformed  stars  ; 
those  clusters  of  stars  which  are  so  dis- 
tant as  not  to  be  distinctly  seen,  are,  from 
their  cloudy  appearance,  comprised  ua- 


Fixed  Stars.  59 

der  the  name  of  nebulce  ;  and  that  light- 
coloured  irregular  circle  or  band  which 
encompasses  the  heavens,  and  is  distin- 
guishable from  the  etherial  blue  by  its 
brilliancy  ;  that  shining  zone,  which 
owes  its  splendour  to  the  innumerable 
stars  of  which  it  is  formed,  and  which 
passes  through  many  of  the  constellations 
in  its  ample  range,  is  called  the  Galaxy^ 
the  via  lactea,  or  the  milky  way. 

The  idea  of  classing  the  stars  under 
well  known  forms  probably  originated 
with  the  Egyptian  shepherds,  who  dur- 
ing the  silent  watches  of  the  night  (as 
they  slept  in  the  open  air)  had  no  other 
objects  to  contemplate  than  those  which 
the  starry  heavens  presented  ;  among 
these,  assisted  by  the  powers  of  a  fertile 
imagination,  they  discovered  a  distant 
resemblance  of  such  things  as  they  were 
most  familiar  with.  The  shepherds  thus 
conceiving  the  figures  of  things  in  the 
firmament,  the  poets  embellished  the  il- 
lusion with  the  fictions  of  mythology, 
till  the  heavens  were,  as  it  were,  filled 
with  these  imaginary  creatures,  and  these 
were  increased  in  after  ages,  and  served 
astronomers  in  their  accounts  of  the  star- 


60  Fixed  Stars. 

ry  heavens,  as  the  present  divisions  of 
the  earth  help  geographers  in  the  descrip- 
tion of  the  globe. 

The  twelve  constellations  which  sur- 
round the  ecliptic,  commonly  called  the 
twelve  signs  of  the  zodiac,  are  the  fol- 
lowing— Aries  the  Ram,  Taurus  the  Bull, 
Gemini  the  Twins,  Cancer  the  Crab,  Leo 
the  Lion,  Virgo  the  Virgin,  Libra  the 
Balance,  Scorpio  the  Scorpion,  Sagittar- 
rius  the  Archer,  Capricornus  the  Goat, 
Aquarius  the  Water-bearer,  and  Pisces 
the  Fishes  ;  and  they  are  noted  on  globes, 
&c.  in  the  following  manner  : — 
Aries.  Taurus.  Gemini,  Cancer.  Leo.  Virgo. — Libra. 

T        8          n  ©       SI      ?>%        =*= 

Scorpio.  Saggitturrius.  Capricornus.  Aquarius.  Pisrts. 
Til  $  V?  X 

The  former  six  are  called  northern,  and 
the  latter  southern  signs  ;  because  the 
former  possess  that  half  of  the  ecliptic 
which  lies  to  the  northward  of  the  equi- 
noctial ;  and  the  latter  that  which  lies  to 
the  southward.  The  northern  are  our 
summer  signs,  the  southern  our  winter 
ones. 

As  these  twelve  signs  answer  to  the 
twelve   months  in  the  year,  it   is  a  very 


Fixed  Stars.  61 

probable  conjecture  that  the  figures  un- 
der which  they  are  represented  are  de- 
scriptive of  the  seasons  of  the  year,  01* 
months,  in  the  sun's  path  ;  thus,  the  first 
sign  Aries,  denotes,  that,  about  the  time 
when  the  sun  enters  that  part  of  the 
ecliptic,  the  lambs  begin  to  follow  the 
sheep  ;  that  on  the  Sun's  approach  to  the 
second  constellation,  Taurus  the  Bull,  is 
about  the  time  of  the  cows  bringing  forth 
their  young.  The  third  sign,  now  Ge- 
mini, was  originally  two  kids,  and  signi- 
fied the  time  of  the  goats  bringing  forth 
their  young,  which  are  usually  two  at  a 
birth,  while  the  former,  the  sheep  and 
cow,  commonly  produce  only  one.  The 
fourth  sign,  Cancer,  the  Crab,  an  animal 
that  goes  side-ways  and  backwards,  was 
placed  at  the  northern  solstice,  the  point 
where  the  sun  begins  to  return  back  again 
from  the  north  to  the  southward.  The 
fifth  sign,  Leo,  the  Lion,  as  being  a  very 
furious  animal,  was  thought  to  denote  the 
heat  and  fury  of  the  burning  sun,  \vhen 
he  has  left  Cancer,  and  entered  the  next 
sign  Leo.  The  succeeding  constellation, 
the  sixth  in  order,  received  the  sun  at  the 
time  of  ripening  corn  and  approaching 


62  Fixed  Stars. 

harvest ;  which  was  aptly  expressed  by 
one  of  the  female  reapers,  with  an  ear  of 
corn  in  her  hand,  viz.  Virgo,  the  Maid. 
The  ancients  gave  to  the  next  sign,  Scor- 
pio, two  of  the  twelve  divisions  of  the 
zodiac  ;  autumn,  which  affords  fruits  in 
great  abundance,  affords  the  means  and 
causes  of  diseases,  and  the  succeeding 
time  is  the  most  unhealthy  of  the  year  ; 
expressed  by  this  venomous  animal,  here 
spreading  out  its  long  claws  into  one  sign, 
as  threatening  mischief,  and  in  the  other 
brandishing  his  tail  to  denote  the  comple- 
tion of  it.  The  fall  of  the  leaf  was  the 
season  of  the  ancient  hunting  ;  for  which 
reason  the  stars  which  marked  the  sun's 
place  at  this  season,  into  the  constellation 
Sagittary,  a  huntsman  with  his  arrows 
and  his  club,  the  weapon  of  destruction 
for  the  large  creatures  he  pursued.  The 
reason  of  the  Wild  Goat's  being  chosen  to 
mark  the  southern  solstice,  when  the  suti 
has  attained  his  extreme  limit  that  way, 
and  begins  to  return  and  mount  again  to 
the  northward,  is  obvious  enough  ;  the 
character  of  that  animal  being  that  it  is 
mostly  climbing,  and  ascending  some 
mountain,  as  it  browses.  There  yet  re- 


Fixed  Stars.  63 

main  two  of  the  signs  of  the  zodiac  to 
be  considered  with  regard  to  their  origin, 
viz.  Aquarius  and  Pisces.  As  to  the 
former,  it  is  to  be  considered  that  the  win- 
ter is  a  wet  and  uncomfortable  season  ; 
this  therefore  was  expressed  by  Aquari- 
us, the  figure  of  a  man  pouring  out  water 
from  an  urn.  The  last  of  the  zodiacal 
constellations  was  Pisces,  a  couple  of 
fishes  tied  together,  that  had  been  caught; 
the  lesson  was,  The  severe  season  is 
over  ;  your  flocks  do  not  yet  yield  then- 
store,  but  the  seas  and  rivers  are  open, 
and  there  you  may  take  fish  in  abun- 
dance. 

With  respect  to  the  distances  of  the 
fixed  stars,  they  are  so  extremely  remote, 
that  we  have  no  distances  in  the  planeta- 
ry system  to  compare  to  them. 

The  distance  of  the  star  Draconis  (a 
star  of  the  fifth  magnitude)  appears,  by 
Dr.  Bradley's  observations,  to  be  at  least 
400,000  times  that  of  the  sun,  and  the 
distance  of  the  nearest  fixed  star  not  less 
than  40,000  diameters  of  the  earth's  an- 
nual orbit ;  that  is,  the  distance  from  the 
earth,  of  the  former  at  least  38,000,000,- 
000,000  miles,  and  the  latter  not  less  than 


64-  Fixed  Stars. 

7,600,000,000,000  miles.  As  these  dis- 
tances are  immensely  great,  it  may  both 
be  amusing,  and  help  to  a  clearer  and 
more  familiar  idea,  to  compare  them  with 
the  velocity  of  some  moving  body,  bj 
which  they  may  be  measured. 

The  swiftest  motion  we  know  of,  is 
that  of  light,  which  passes  from  the  sun 
to  the  earth  in  about  eight  minutes  ;  and 
yet  this  would  be  above  six  years  travers- 
ing the  first  space,  and  near  a  year  and  a 
quarter  in  passing  from  the  nearest  fixed 
star  to  the  earth.  But  a  cannon-ball, 
moving  on  a  medium  at  the  rate  of  about 
twenty  miles  in  a  minute,  would  be 
3,800,000  years  in  passing  from  Draco- 
nis  to  the  earth,  and  760,000  years  pass- 
ing from  the  nearest  fixed  star.  Sound, 
which  moves  at  the  rate  of  about  thir- 
teen miles  in  a  min.  would  be  5,60O,OOO 
years  traversing  the  former  distance,  and 
1,128,000  in  passing  through  the  latter. 
The  celebrated  Kuygens  pursued  specu- 
lations of  this  kind  so  far,  as  to  believe 
it  not  impossible,  that  there  may  be  stars 
at  such  inconceivable  distances,  that  their 
light  has  not  yet  reached  the  earth  sincp 
the  creation. 


Fixed  Stars.  65 

Though  the  number  of  the  stars  ap- 
pears to  be  immensely  great ;  yet  have 
astronomers  long  since  ascertained  the 
number  of  such  as  are  visible  to  the 
eye,  which  are  much  fewer  thaii  at  first 
sight  could  be  imagined.  Of  the  3000 
contained  in  Flamstead's  catalogue,  there 
are  many  that  are  only  visible  through  a 
telescope  ;  and  a  good  eye  scarcely  ever 
sees  more  than  a  thousand  at  the  same 
time  in  the  clearest  heaven  ;  the  appear- 
ance of  innumerable  more,  that  are  fre- 
quent in  clear  winter  nighty,  arising  from 
our  sight's  being  deceived  by  their  twink- 
ling, and  from  our  viewing  them  confu- 
sedly, and  not  reducing  them  to  any  or- 
der. But  a  good  telescope,  directed  in- 
differently to  almost  any  point  of  the  hea- 
vens, discovers  multitudes  that  are  lost  to 
the  naked  eye  ;  particularly  in  the  milky 
way.  And  F.  de  Rheita  affirms,  that 
he  has  observed  above  2000  stars  in  the 
single  constellation  of  Orion.  The  same 
author  found  above  188  in  the  Pleiades. 
Galileo  found  eighty  in  the  space  of  the 
belt  of  Orion's  sword,  twenty-one  in  the 
nebulous  star  of  his  head,  and  above  50O 
in  another  part  of  him,  within  the  com- 
F 


66  Fixed  Stars. 

pass  of  one  or  two  degrees  of  space,  and 
more  than  forty  in  the  nebulous  star 
Prsesepe,  and  the  recent  disco\7eries  of 
Dr.  Herschel  have  proved  the  fixed  stars 
to  be  immense,  their  regions  unbounded, 
and  perhaps  infinite  ! 

As  the  stars,  contrary  to  the  moon  and 
planets,  shine  like  our  sun,  by  their  own 
native  light,  astronomers  suppose  that 
each  of  them  is  a  sun,  with  its  system  of 
inhabited  worlds  revolving  round  it.  Un- 
der this  idea  or  persuasion,  of  how  innu- 
merable a  family  do  we  seem  to  make  a 
part !  The  immensity  of  the  universe  be- 
comes peopled  with  fellow  beings,  and 
we  feel  an  interest  in  what  appears  to  be 
going  on  at  distances  so  vast,  that  what 
we  see,  as  in  time  present,  we  have  rea- 
son to  believe  (swift,  as  is  the  progress  of 
light,  darting  from  the  spheres)  must 
have  happ;n<,  J  many  ages  ago.  Under 
the  idea  of  the  universe  being  replenish- 
ed with  human  brings,  how  magnificent, 
how  awful,  are  tne  spectacles  that  present 
themselves  to  the  observer  of  the  hea- 
vens !  The  creature  of  a  day,  of  a  few 
fleeting  moments,  seems  to  obtain  a 
glimpse  of  a  nqw  creation,  a  glimpse  of 


Fixed  Stars.  67 

the  end  of  time,  in  the  passing  away  of  a 
system. 

What  an  amazing  conception,  if  hu- 
man imagination  can  conceive  it,  does 
this  give  of  the  works  of  the  Creator! 
Thousands  of  thousands  of  suns,  multi- 
plied without  end,  and  ranged  ail  around 
us,  at  immense  distances  from  each  oth- 
er, attended  by  ten  thousand  times  ten 
thousand  worlds,  all  hung  loosens  it  were, 
in  boundless  space, — upheld  by  nothing, 
confined  by  nothing, — yet  preserved  in 
their  rapid  course,  calm,  regular  and  har- 
monious, invariably  keeping  the  paths 
assigned  them  by  the  sovereign  Artificer. 


68     The  Earth  considered  as  a  Planet. 

CHAP.  V. 

Of  the  Earth  considered  as  a  Planet, 

THE  Earth  goes  round  the  sun  in  365 
days  5  hours  49  minutes,  from  an  equi- 
nox or  solstice  to  the  same  again  ;  but 
from  any  fixed  star  to  the  same  again, 
as  seen  from  the  sun,  in  365  days, 6  hours 
and  nine  minutes ;  the  former  being  the 
length  of  the  tropical  ijear,  and  the  latter 
the  length  of  the  sidereal. 

The  motion  of  the  earth  in  common 
with  the  rest  of  the  planets  about  the 
sun,  is  in  the  order  of  the  signs  of  the 
zodiac  ;  that  is,  from  west  to  east.  This 
zone  or  belt,  as  has  been  mentioned,  goes 
round  the  heavens  ;  and  along  the  middle, 
of  it  is  the  ecliptic,  or  circle  which  the 
earth  describes  annually  as  seen  from 
the  sun ;  and  which  the  sun  appears  to 
describe  as  seen  from  the  earth. 

Besides  this  annual  revolution  of  the 
earth  about  the  sun,  in  the  ecliptic  ;  the 


The  Earth  considered  as  a  Planet.  69 

earth  turns  round  upon  its  own  axis  in 
24  hours. 

The  turning  of  the  earth  upon  its  own 
axis  every  24  hours,  whilst  it  moves 
round  the  sun  in  a  year,  we  may  conceive 
by  the  running  of  a  howl  on  a  bowling 
green ;  in  which  not  only  the  center  of 
the  bowl  hath  a  progressive  motion  on  the 
green  ;  but  the  bowl  in  its  going  forward, 
from  one  part  of  the  green  to  another, 
turns  round  about  its  own  axis. 

The  turning  of  the  earth  on  its  axis, 
makes  the  difference  of  day  and  night ;  it 
being  day  in  those  parts  of  the  earth, 
which  are  turned  towards  the  sun  ;  and 
night  in  those  parts  which  are  in  the 
shade,  or  turned  from  the  sun. 

The  annual  revolution  of  the  earth  in 
the  ecliptic,  is  the  cause  of  the  different 
seasons,  and  of  the  several  lengths  of  days 
and  nights,  in  every  part  of  the  world,  in 
the  course  of  the  year. 

But  before  we  enter  upon  the  more 
particular  illustration  of  the  diurnal  and 
annual  motions  of  the  earth,  together 
with  the  different  lengths  of  days  and 
nights,  and  all  the  beautiful  variety  of 
seasons,  depending  on  those  motions,  it 
F2 


70  The  Earth  considered  as  a  Planet. 

may  be  necessary  to  make  the  reader  ac- 
quainted with  the  principle  circles  of  the 
globe,  as  they  will  greatly  assist  him  in 
comprehending  those  phenomena. 

This  information  he  may  attain  suffi- 
ciently for  his  present  purpose  in  a  quar- 
ter of  an  hour,  if  he  sets  the  ball  of  a  ter- 
restrial  globe  before  him,  or  looks  at  the 
figure  of  it,  wherein  these  circles  are 
drawn  and  named. 

The  Poles  are  the  two  extremities  of 
the  earth's  axis  ;  or  those  points  where 
the  imaginary  line,  round  which  it  per- 
forms its  daily  revolutions,  meets  the 
earth's  surface  ;  that  which  is  directed 
towards  the  most  northern  point  of  the 
heavens,  being  called  the  north  pole  ;  and 
that  which  is  directed  towards  tke  most 
southern  point,  the  south  pole  ;  so  that 
they  are  di  am  e  trie  ally  opposite  to  each 
other,  and  always  preserve  the  same  rela- 
tive situation.  It  is  also  to  be  observed, 
that  these  two  points  have  not  been  arbi- 
trarily assumed  by  geographers  and  as- 
tronomers, to  answer  their  particular  pur- 
poses, as  they  are  pointed  out  to  us  by 
the  nature  and  constitution  of  the  globe, 
and  are  easily  distinguished  from  all 


/  The  Earth  considered  as  a  Planet.  71 

others.  The  nearer  we  approach  to  them, 
the  more  we  find  the  earth  becomes  bar- 
ren and  inhospitable  ;  so  that,  under  the 
poles,  the  cold  is  so  excessive,  that  the 
country  must  be  nearly  uninhabitable. 
Imagine  now  a  circle  to  be  drawn  round 
the  globe,  exactly  in  the  middle,  between 
these  two  points,  and  this  will  be  the 
Equator  ;  which,  properly  speaking,  is  a 
great  circle  of  the  earth,  that  separates 
the  northern  from  the  southern  hemis- 
phere, and  is  every  where  at  an  equal  dis- 
tance from  the  poles.  This  circle  is  al- 
so no  less  remarkable,  on  account  of  its 
situation,  than  the  poles  ;  the  heat  being 
here  almost  as  intense  as  the  cold  is 
there.  Every  place  is  said  to  have  north 
or  south  latitude  as  it  is  on  the  northern 
or  southern  side  of  this  great  circle. 

The  Tropics  are  lesser  circles  parallel 
to  the  equator,  and  each  of  them  is  23 1 
degrees  from  it ;  a  degree  in  this  sense 
being  the  360th  part  of  any  great  circle 
which  divides  the  earth  into  two  equal 
parts.  The  northern  tropic  touches  the 
ecliptic  at  the  beginning  of  Cancer,  and 
is  thence  called  the  Tropic  of  Cancer  ; 
the  southern  tropic,  touching  the  ecliptic 


72   The  Earth  considered  as  a  Planet. 

at  the  beginning  of  Capricorn,  is  therefore 
called  the  Tropic  of  Capricorn. 

The  Arctic  Circle  has  the  north  pole  for 
its  centre,  and  is  just  as  far  from  the  north 
pole  as  the  tropics  are  from  the  equator ; 
and  the  Antarctic  Circle  (hid  by  the  sup- 
posed convexity  of  the  figure)  is  just  as 
far  from  the  south  pole,  every  way  round , 
it. 

The  circles  12. 1.  2.  3.  4.  &c.  are  meri- 
dians to  all  places  they  pass  through  ;  and 
we  must  suppose  thousands  more  to  be 
drawn,  because  every  place  that  is  ever 
so  little  to  the  east  or  west  of  any  other 
place,  has  a  different  meridian  from 
that  other  place.  All  the  meridians  meet 
in  the  poles  ;  and  whenever  the  sun's  cen- 
ter is  passing  over  any  meridian,  in  his 
apparent  motion  round  the  earth,  it  is 
mid-day  or  noon  to  all  places  on  that  me- 
ridian. The  longitude  of  a  place  is  its 
distance  east  or  west  from  the  first  meri- 
dian, reckoned  in  degrees,  minutes,  &c. 
upon  the  equator.  Supposing  we  call 
London  the  first,  it  will  cut  the  equator 
in  two  opposite  points  at  the  distance  of 
one  hundred  and  eighty  degrees  each 
way  ;  and  as  the  equator  is  the  boundary 


The  Earth  considered  as  a  Planet.  73 

which  separates  the  northern  hemisphere 
from  the  southern,  so  this  circle  may  be 
considered  as  the  boundary  which  sepa- 
rates the  eastern  hemisphere  from  the 
western. 

The  broad  space  lying  between  the 
tropics,  like  a  girdle  surrounding  the 
globe,  is  called  the  Torrid  Zone,  because 
the  sun  is  at  one  time  or  other  perpendi- 
cular over  every  part  of  it,  and  extreme- 
ly torrifies  or  heats  it.  The  space  be- 
tween the  tropic  of  Cancer  and  arctic 
circle  is  called  the  North  Temperate  Zone; 
that  between  the  tropic  of  Capricorn  and 
the  antarctic  circle,  the  South  Temperate 
Zone:  from  their  enjoying  a  mean  or 
moderate  degree  of  heat ;  and  the  two 
circular  spaces  bounded  by  the  polar  cir- 
cles are  the  two  Frigid  Zones  ;  so  named 
because  of  the  intense  cold  which  reigns 
in  those  regions  the  greatest  part  of  the 
year  ;  and  they  are  denominated  north  or 
south,  from  that  pole  which  is  in  the  cen- 
ter of  the  one  or  the  other  of  them. 


Of  the  Seasons,  £s?c. — -Nature  is  always 
grand  in  her  designs,  sublimity  and  sim- 
plicity are  the  striking  characteristics  of 


74  The  Earth  considered  as  a  Planet. 

her  workmanship.  From  a  few  simple 
principles  she  produces  the  most  aston- 
ishing effects,  and  charms  us  no  less  by 
the  infinite  diversity  of  her  operations, 
than  by  the  skill  and  contrivance  which 
are  manifested  in  the  performance  of 
them.  Of  all  the  effects  resulting  from 
her  laws  none  is  more  simple  nor  more 
pleasing  to  a  philosophic  mind  than  the 
provision  that  is  made  for  the  alternate 
succession  of  day  and  night,  and  the 
regular  return  of  the  seasons.  The  phe- 
nomena depend  upon  the  most  simple 
and  evident  principle.  We  have  the  one 
merely  from  the  rotation  of  our  globe  on 
its  axis,  and  the  other  from  the  inclina- 
of  that  axis  to  the  plane  of  its  orbit. 

The  axis  of  the  earth  being  inclined 
23-|  degrees  to  the  plane  of  its  orbit, 
makes  it,  in  moving  round  the  sun,  have 
sometimes  one  of  its  poles  and  some- 
times the  other  nearer  that  luminary. 

The  absence  of  the  sun's  light  pro- 
duces a  proportionable  degree  of  cold ; 
hence  the  seasons  are,  in  the  northern 
and  southern  parts  of  the  globe,  distinctly 
marked  by  different  degrees  of  heat  and 
sold.  It  is  this  annual  turning  of  the 


The  Earth  considered  as  a  Planet.  75 

poles  towards  the  sun,  that  occasions  the 
very  long  days  in  the  northern  and  south- 
ern parts.  It  is  owing  to  the  same  cause, 
that  the  sun  seems  to  rise  higher  in  the 
heavens  during  summer  than  in  winter  ; 
and  this  alternate  sinking  and  rising  is 
perceptible  over  the  whole  globe. 

In  order  to  illustrate  this  subject  let 
us  now  take  a  view  of  the  earth  in  its  an- 
nual course  round  the  sun,  considering' 
its  orbit  as  having  no  inclination  |  and 
its  axis  as  inclining  23 -|  degrees  from 
a  line  perpendicular  to  the  plane  of  its 
orbit,  and  keeping  the  same  oblique  di- 
rection in  all  parts  of  its  annual  course  ; 
or,  as  commonly  termed,  keeping  always 
parallel  to  itself. 

In  Fig.  2  let  S  represent  the  sun,  the 
four  globes  the  earth  in  different  parts  of 
its  orbit,  receiving  from  its  changing  po- 
sition the  varying  seasons.  Ns  its  axis, 
N  its  north  pole,  s  its  south  pole.  As  it 
goes  round  the  sun,  according  to  the  order 
of  the  signs  of  the  zodiac,  its  axis  Ns 
keeps  the  same  obliquity,  and  is  still  par- 
allel to  itself. 

We  shall  commence  its  annual  round  at 
the  first  point  of  Libra,  when  the  sun,  as 


76   The  Earth  considered  as  a  Planet. 

seen  from  the  earth  will  appear  to  enter 
Aries.  At  this  time,  namely  the  20th  of 
March,  the  sun  will  be  in  the  equinoctial, 
and  all  parts  of  the  earth  will  be  equally 
enlightened  from  pole  to  pole,  and  the 
days  and  nights  equal  all  over  the  world, 
for  every  part  comes  into  the  light  at  six 
in  the  morning,  and  goes  into  the  dark  at 
six  in  the  evening.  As  the  earth  passes 
on  in  the  order  of  the  signs,  in  about  three 
months,  viz.  on  the  21st  of  June,  it  will 
arrive  at  the  beginning  of  Capricorn,  and 
the  sun,  as  seen  from  the  earth,  will  ap- 
pear at  the  beginning  of  Cancer  ;  during 
which  time,  by  the  inclined  position  of  the 
earth's  axis,  the  north  pole  will  have  gra- 
dually advanced  into  the  enlightened 
hemisphere  ;  so  that  the  whole  northern 
polar  circle  will  be  therein,  while  the 
southern  pole  ir>  immerged  in  obscurity ; 
the  northern  parts  of  the  world  will  enjoy 
long  days,  while  they  are  short  in  the 
southern  parts.  In  this  situation  of  the 
earth  the  tropic  of  Cancer  is  in  the  light 
from  five  in  the  morning  till  seven  at  night, 
the  parallel  of  London  from  a  quarter  be- 
fore four  till  a  quarter  after  eight ;  and 
the  polar  circle  just  touches  the  dark,  so 


The  Earth  considered  as  a  Planet.  77 

that  the  sun  has  only  the  lower  half  of  his 
disk  hid  from  the  inhabitants  on  that  cir- 
cle for  a  few  minutes  about  midnight. 

After  this  the  days  begin  to  shorten  in 
the  northern  parts  of  the  world,  and  the 
nights  lengthen  in  proportion  as  the  earth 
advances  to  the  first  point  of  Aries,  at 
which  it  arrives  on  the  23d  of  September, 
when  the  sun,  as  seen  from  the  earth, 
will  appear  in  .Libra.  On  this  day  the 
sun  will  be  in  the  equinoctial  again,  and 
the  days  and  nights  will  again  be  equal 
all  over  the  globe.  As  the  earth  pro- 
ceeds on  its  orbit  from  this  point,  the 
north  pole  gradually  goes  into  the  dark  ; 
and  the  south  pole  advances  into  the  err- 
lightened  hemisphere  ;  and  on  the  22d  of 
December,  when  the  earth  enters  Cancer, 
and  the  sun  appears  at  Capricorn,  the 
north  pole  will  be  as  far  as  it  can  be  in  the 
dark,  which  is  23-|  degrees,  equal  to 
the  inclination  of  the  earth's  axis  from  a 
perpendicular  to  its  orbit :  and  then,  the 
northern  parts  are  as  much  in  the  dark  as 
they  were  in  the  light  on  the  21st  oijime; 
the  winter  nights  being  as  long  as  the 
summer  days,  and  the  winter  days  as 
short  as  the  summer  nights. 
G 


78   The  Earth  considered  as  a  Planet. 

Thus  we  see  while  the  earth  is  moving 
from  Libra  through  Capricorn  to  Aries, 
the  north  pole  remains  in  the  illuminated 
hemisphere,  and  will  therefore  have  six 
months  of  continual  day.  But  in  the 
other  half  year,  while  the  earth  is  moving 
from  Aries  through  Cancer  to  Libra,  the 
north  pole  is  turned  from  the  sun,  and 
therefore  in  darkness,  but  the  south  pole 
is  in  the  illuminated  hemisphere.  Hence 
it  is  easy  to  perceive,  that  the  inhabitants 
of  the  southern  hemisphere  have  the  same 
vicissitudes  with  those  of  the  northern, 
though  not  at  the  same  time,  it  being  win- 
ter in  one  hemisphere  when  it  is  summer 
in  the  other. 

During  this  annual  course  of  the  earth 
there  are  four  days  in  her  orbit  particu- 
larly to  be  remarked  ;  these  astronomers 
have  distinguished  by  the  names  of  the 
solstitial  and  equinoctial  days.  The  sol- 
stitial days  are  those  on  which  the  sun  ap- 
pears most  to  the  northward  and  the 
southward  ;  they  are  our  longest  and 
shortest  days,  and  are  called  the  -winter 
and  summer  solstices.  The  equinoctial 
days  are  those  on  which  the  sun  appears 
in  the  equator,  and  the  days  are  equal  to 


The  Earth  considered  as  a  Planet.  79 

the  nights,  which  is  twice  in  every  annual 
revolution  of  the  earth,  and  are  called  the 
autumnal  and  vernal  equinoxes. 

The  earth's  annual  motion  causes  an 
apparent  daily  declination  of  the  sun,  or 
in  other  words,  he  appears  at  different  dis- 
tances from  the  equator  every  diurnal 
turn  of  the  earth  on  its  axis.  Thus,  about 
the  22d  of  December,  when  the  earth  is 
in  Cancer,  the  sun  will  be  over  the  tropic 
of  Capricorn  ;  and  consequently,  by  the 
earth's  rotation  on  its  axis,  the  inhabitants 
of  every  part  of  this  circle  will  success- 
ively have  the  sun  in  their  zenith,  or,  in 
other  words,  he  will  be  vertical  to  them 
that  day  at  noon.  About  the  20th  of 
March  the  earth  is  at  Libra,  and  the  sun 
will  then  appear  in  Aries  ;  a  central  solar 
ray  will  terminate  upon  the  surface  of  the 
earth  in  the  equator  ;  and  therefore  the 
sun  appears  to  be  carried  round  in  the 
celestial  equator,  and  is  successively  ver- 
tical to  those  who  live  under  that  circle. 
About  the  21st  of  June,  when  the  earth 
is  in  Capricorn,  a  central  solar  ray  ter- 
minates on  the  surface  of  the  earth,  in 
the  northern  tropic,  and  for  that  day  the 
sun  appears  to  be  carried  round  in  the  tro- 


80  The  Earth  considered  as  a  Planet, 

pic  of  Cancer,  and  is  vertical  to  those 
who  live  under  that  circle.  About  the 
23d  of  September  the  earth  is  in  Aries, 
and  the  sun  in  Libra,  and  the  central  so- 
lar ray  again  terminates  at  the  equator  ; 
consequently  the  sun  again  appears  in  the 
celestial  equator,  and  is  vertical  to  those 
who  live  under  it. 

We  have  seen,  that,  as  the  sun  appears 
to  move  in  the  ecliptic,  from  the  vernal 
equinox  to  the  tropic  of  Cancer,  it  gets 
to  the  north  of  ths  equator,  or  its  decli- 
ivition  towards  our  pole  increases.  There- 
fore, from  the  vernal  equinox,  when  the 
days  and  nights  are  equal,  till  the  sun 
comes  to  the  tropic  of  Cancer,  our  days 
lengthen,  and  our  nights  shorten  ;  but, 
when  the  sun  comes  to  the  tropic  of  Can- 
cer, it  is  then  in  its  utmost  northern  lim- 
it, and  returns  in  the  ecliptic  to  the  equa- 
tor again.  During  this  return  of  the  sun, 
its  declination  tov/urds  our  pole  decrea»^s, 
and  consequently  the  days  decrease,  and 
rights  increase,  till  the  sun  is  ar- 
rived in  die  equator 'again,  and  is  in  the 
autumnal  equinoctial  point,  when  the 
(I  ivs  ts  will  ngain  be  equal.  As  the 

sun  moves  from  thence  towards  the  tro- 


The  Earth  considered  as  a  Planet,  81 

pic  of  Capricorn,  it  gets  to  the  south  of 
the  equator ;  or  its  declination  towards 
the  south  pole  increases.  Therefore,  at 
that  time  of  year,  our  days  shorten,  and 
our  nights  lengthen,  till  the  sun  arrives 
at  the  tropic  of  Capricorn;  but,  when 
the  sun  is  arrived  there,  it  is  then  at  its 
utmost  southeren  limit,  and  returns  in 
the  ecliptic  to  the  equator  again.  Dur- 
ing this  return,  its  distance  from  our  pole 
lessens,  and  consequently  the  days  will 
lengthen,  as  the  nights  will  shorten,  till 
they  become  equal,  when  the  sun  is  come 
round  to  the  vernal  equinoctial  point. 

The  earth's  orbit  being  elliptical,  and 
the  sun  constantly  keeping  in  its  lower 
focus,  which  is  1,377,000  miles  from  the 
middle  point  of  the  longer  axis,  the  earth 
comes  twice  so  much,  or  2, 754,000  miles 
nearer  the  sun  at  one  time  of  the  year 
than  at  another:  for  the  sun  appearing 
under  a  larger  angle  in  our  winter  than 
summer,  proves  that  the  earth  must  be 
nearer  the  sun  in  the  former  season  than 
in  the  latter.  How  then  does  it  happen 
that  we  have  not  the  hottest  weather 
when  we  are  at  the  least  distance  from  the 
sun  : — The  earth  is  above  2,000,000  of 
02 


82   The  Earth  considered  as  a  Planet. 

miles  nearer  to  the  sun  in  December  than 
it  is  in  June,  and  yet  in  June  it  is  the 
middle  of  summer,  and  in  December  the 
depth  of  winter,  which  seems  a  paradox. 
To  obviate  this  apparent  contradiction* 
it  may  be  observed  that  the  eccentricity 
of  the  earth's  orbit  bears  no  greater  pro- 
portion to  the  earth's  mean  distance  from 
the  sun  than  about  1  to  60,  and  therefore 
this  small  difference  of  distance  cannot 
occasion  any  great  variation  in  the  heat 
and  cold  of  the  different  seasons.  But 
the  principal  cause  of  this  difference  is, 
that  in  winter  the  sun's  rays  fall  so  ob- 
liquely upon  us,  that  any  given  number 
of  them  is  spread  over  a  much  greater 
portion  of  the  earth's  surface  where  we 
live  ;  and  therefore  each  point  must  then 
have  fewer  rays  than  in  summer.-— 
Moreover,  there  comes  a  greater  degree 
of  cold  in  the  long  winter  nights,  than 
there  can  return  of  heat  in  so  short  days  ; 
1  on  both  these  accounts  the  cold  must 
increase.  But  in  summer  the  sun's  rays 
fall  more  perpendicularly  upon  us,  and 
therefore  com*  with  greater  force,  and  in 
greater  numbers  i>..  the  same  place  ;  and 
by  their  kr.ig  continuance,  a  much  great- 


The  Earth  considered  as  a  Planet.  83 

er  degree  of  heat  is  imparted  by  day  than 
can  fly  off  by  night,  so  that  the  heat,  on 
all  these  accounts,  will  continue  to  in- 
crease. 

Thus  we  see  by  what  simple  principles 
the  bountiful  Author  of  Nature  has  pro- 
vided us  with  such  a  pleasing  succession 
of  scenes,  —  summer,  winter,  spring,  and 
autumn,  lead  us*  insensibly  through  the 
varied  circle  of  the  year  ;  and  are  no  less 
pleasing  to  the  mind,  than  necessary  to- 
wards bringing  to  maturity  the  various 
productions  of  the  earth.  Whether  the 
sun  flames  in  the  solstice,  or  pours  his 
mild  effulgence  from  the  equator,  we 
equally  rejoice  in  his  presence,  and  adore 
that  omniscient  Being  who  gave  him  his 
appointed  course,  and  prescribed  the 
bounds  which  he  cannot  pass. 


by  the  daily  motion  of  the  earth 
the  rising  sun  comes  within  18  degrees 
of  the  horizon,  we  perceive  a  faint  light 
begin  to  appear,  which  increases,  and  the 
magnificent  theatre  oi  the  universe  opens 
gradually  to  our  view  —  being  fully  risen, 
he  rides  in  all  his  brightness  through  the 
vault  of  heaven,  and  approaches  the  west- 


84  The  Earth  considered  as  a  Planet. 

era  boundary  of  our  sight,  when  the  light 
begins  to  decrease,  and  gradually  dimin- 
ishes till  he  is  18  degrees  below  the  hori- 
zon, when  dark  night  commences.  This 
intermediate  light  is  called  the  crepuscu- 
lum,  or  the  morning  and  evening  twilight. 

As  the  sun  enlightens  only  one  half  of 
the  earth  at  once  as  it  turns  round  its 
axis,  he  rises  to  some  places  at  the  same 
moments  of  absolute  time  when  he  sets 
to  others  ;  and  when  it  is  mid-day  to 
some  places,  it  is  mid-night  to  others. 

To  every  place  15  degrees  eastward 
from  any  given  meridian,  it  is  noon  an 
hour  sooner  than  on  that  meridian ;  be- 
cause their  meridian  comes  to  the  sun  an 
hour  sooner  ;  and  to  all  places  15  de- 
grees westward,  it  is  noon  an  hour  later 
because  their  meridian  comes  an  hour 
later  to  the  sun,  and  so  on :  every  15  de- 
grees of  motion  causing  an  hour's  differ 
ence  of  time.  Therefore  they  who  have 
noon  an  hour  later  than  we,  have  their 
meridian,  that  is,  their  longitude,  15  de- 
grees westward  from  us  :  and  they  who 
have  noon  an  hour  sooner  than  we,  have 
their  meridian  15  degrees  eastward  from 
ours  ;  and  so  for  every  hour's  difference 


The  Earth  considered  as  a  Planet.  85 

of  time  15  degrees  difference  of  longi- 
tude. Consequently,  if  the  beginning  or 
ending  of  a  lunar  eclipse  be  observed, 
suppose  at  London,  to  be  exactly  at  mid- 
night, and  in  some  other  place  at  11  at 
night,  that  place  is  15  degrees  westward 
from  the  meridian  of  London  ;  if  the  same 
eclipse  be  observed  at  one  in  the  morn- 
ing at  another  place,  that  place  is  15  de- 
grees eastward  from  the  said  meridian. 


Of  the  Precession  of  the  Equinoxes,  &?c. 
— Beside  the  changes  in  the  length  ol  the 
days  already  described  in  the  different 
seasons,  there  is  another  sort  of  change, 
not  so  obviously  noticeable.  The  day 
and  night  together,  or,  in  general,  24 
hours,  form  the  natural  or  solar  day  ;  and 
this  period  of  time  also  varies  in  its 
length.  The  inequality  of  the  solar  day 
is  produced  by  two  causes,  either  o£ 
which  singly  would  yield  the  effect  ; 
these  are  the  obliquity  of  the  ecliptic,  and 
the  earth's  unequal  motion  therein.  The 
earth's  motion  on  its  axis  being  uniform 
and  equal  at  all  times  of  the  year,  its  days 
would  be  equal,  if  its  orbit  were  a  perfect 
circle,  and  its  axis  perpendicular  to  the 


86  The  Earth  considered  as  a  Planet. 

plane  of  its  orbit ;  but  the  earth's  annual 
motion  in  an  elliptic  orbit,  causes  the  sun's 
apparent  motion  in  the  heavens  to  be  un- 
equal. When  the  sun's  annual  motion 
in  the  heavens  appears  slowest,  it  is  noon, 
or  12  on  the  sun-dial,  before  it  is  the 
same  hour  on  a  true-going  clock ;  and 
when  quickest,  it  is  12  by  the  clock  be- 
fore the  sun  be  over  our  meridian. 

Although  the  earth  be  said  to  complete 
an  orbit  round  the  sun  in  the  course  of  a 
year,  it  does  not  return  exactly  to  the 
place  it  set  out  from,  neither  is  its  cir- 
cuit completed  exactly  in  a  year.  Adopt- 
ing, therefore,  the  apparent  motion  in- 
stead of  the  real  ;  if  the  sun  set  out  as 
from  any  star,  or  other  fixed  point  in  the 
heavens,  at  the  moment  it  is  departing 
from  the  equinoctial,  or  from  either  tro- 
pic, it  will  come  to  the  same  equinox,  or 
tropic  again,  20  min.  17-  sec.  of  time, 
or  50  sec.  of  a  degree,  before  it  completes 
its  circuit  round  the  heavens,  so  as  to  ar- 
rive at  the  same  fixed  star  or  point  from 
whence  it  sets  out ;  for  the  equinoctial 
points  recede  50  seconds  of  a  degree  west- 
ward every  year,  contrary  to  the  sun's 
annual  progressive  motion.  This  is  call- 
ed the  Precession  of  the  Equinoxes, 


The  Earth  considered  as  a  Planet.  87 

When  the  sun  arrives  at  the  same  equi- 
noctial or  solstitial  point,  he  finishes  what 
we  call  the  tropical  year  ;  which,  by  ob- 
servation, is  found  to  contain  365  days 
5  hours  48  minutes  57  seconds:  and 
when  he  arrives  at  the  same  fixed  star 
again,  as  seen  from  the  earth,  he  completes 
the  sidereal  year,  which  contains  365 
days  6  hours  9  minutes  14~  seconds. 
The  sidereal  year  is  therefore  2O  min- 
utes 17-  seconds  longer  than  the  solar 
or  tropical  year,  and  9  minutes  14 1 
seconds  longer  than  the  Julian  or  civil 
year,  which  we  state  at  365  days  6  hours  : 
so  that  the  civil  year  is  almost  a  meanbe- 
twixt  the  sidereal  and  tropical. 

The  anticipation  of  the  equinoxes,  and 
consequently  of  the  seasons,  is  by  no 
means  owing  to  the  precession  of  the 
equinoctial  and  solstitial  points  in  the 
heavens  (which  can  only  affect  the  appa- 
rent motions,  places  and  declinations  of 
the  fixed  stars)  but  to  the  difference  be- 
tween the  civil  and  solar  year,  which  is 
1 1  minutes  3  seconds  ;  the  civil  year  con- 
taining 365  days  6  hours,  and  the  solar 
year  365  days  5  hours  48  minutes  57 
seconds, 


88   The  Earth  considered  as  a  Planet. 

The  above  11  minutes  3  seconds,  by 
which  the  civil  or  Julian  year  exceeds 
the  solar,  amounts  to  11  days  in  1433 
years,  and  so  much  our  seasons  have  fall- 
en back  with  respect  to  the  days  of  the 
months,  since  the  time  of  the  Nicene 
Council  in  A.  D.  325,  and  therefore  in 
order  to  bring  back  all  the  fasts  and  fes- 
tivals to  the  days  then  settled,  it  was  re- 
quisite to  suppress  1 1  nominal  days.  And 
that  the  same  seasons  might  be  kept  to 
the  same  times  of  the  year  for  the  future, 
to  leave  out  the  bissextile-day  in  February 
at  the  end  of  every  century  of  years  not  di- 
visible by  4  ;  reckoning  them  only  com- 
mon years,  as  the  17th,  18th,  and  19th 
centuries,  viz.  the  years  1700, 1800, 1900, 
£cc.  because  a  day  intercalated  every 
fourth  year  was  too  much,  and  retail, 
the  bissextile-day  at  the  end  of  those  cen- 
turies of  years  which  are  divisible  by  4,  as 
the  16th,  20th,  and  24th  centuries  ;  viz. 
the  years  1600,  2000,  2400,  &c.  Other- 
wise, in  length  of  time,  the  seasons  would 
be  quite  ^reversed  with  regard  to  thr 
months  of  the  year  ;  though  it  would 
have  required  near  23,783  years  to  have 
brought  about  such  a  totaj  change. 


The  Earth  considered  as  a  Planet,  89 

This  new  form  of  reckoning  was  or- 
dained by  Pope  Gregory,  and  is  there- 
fore called  the  Gregorian,  or  the  new 
style,  and  has  been  adopted  by  almost  all 
the  enlightened  nations  of  the  world  ; 
there  are  some,  however,  who  still  reckon 
according  to  the  old  style,  viz.  as  if  no 
alteration  had  been  made  by  Pope  Gre- 
gory. 


H 


9'0  Atmosphere, 

CHAP.  VI. 

Of  the  Air  and  Atmosphere. 

WE  have  already  considered  the  earth 
as  a  planet,  or  one  of  the  great  masses 
of  matter  moving  about  the  sun  ;  we  shall 
now  consider  it  as  it  is  made  up  of  its 
several  parts,  abstracting  from  its  diur- 
nal and  annual  motions. 

The  exterior  part  of  this  our  habitable 
world  is  the  air  or  atmosphere  ;  a  light, 
thin  fluid,  or  springy  body,  that  incom- 
passes  the  solid  earth  on  all  sides,  and 
partakes  of  all  its  motions.,  both  annual 
and  diurnal. 

The  composition  of  that  part  of  our 
atmosphere  properly  called  air,  was  till 
lately  but  very  little  known.  Formerly 
it  was  supposed  to  be  a  simple,  homoge- 
neous, and  elementary  fluid.  But  the 
experiments  of  Dr.  Priestley  and  others 
have  discovered,  that  even  the  purest 
kind  of  air,  which  they  call  vita'. 


Atmosphere.  91 

plilogisticated,  is  in  reality  a  compound, 
and  might  be  artificially  produced  in  va- 
rious ways.  This  dephlogisticated  air,> 
however,  is  but  a  small  part  of  the  com- 
position of  our  atmosphere.  By  accu- 
rate experiments,  the  air  we  usually 
breathe,  is  composed  of  only  one-fourth 
part  of  this  dephlogisticated  air,  or  per- 
haps less,  the  other  three  parts,  or  more, 
consisting  of  what  Dr.  Priestly  calls  phlo~ 
gisticated,  and  M.  Lavoisier,  in  the  new 
chemistry,  mephitzc,  or  azotic  air,  which 
cannot  be  breathed,  and  in  which  ani- 
mals die. 

Though  air  seems  to  be  a  kind  of  re- 
pository, wherein  all  the  poisonous  efflu- 
via arising  from  putrid  and  corrupted  mat- 
ters are  lodged  ;  yet  it  has  a  wonderful 
facilitv  of  purifying  itself,  and  of  deposi- 
ting those  vapours  contained  in  it ;  so 
that  it  never  becomes  noxious  except  in 
particular  places,  arid  for  a  short  time  ; 
the  general  mass  remaining  upon  all  oc- 
casions pretty  much  the  same.  The  way 
in  which  this  purifaction  is  effected  is  dif- 
ferent, according  to  the  nature  of  the  va- 
pour with  which  the  air  is  loaded.  That 
which  most  universally  prevails  is  water ; 


92  Atmosphere. 

and  from  experiments  it  appears,  that  the 
quantity  of  aqueous  vapour  contained 
in  the  atmosphere  is  immense.  Dr. 
Halley,  from  an  experiment  on  the  eva- 
poration from  a  fluid  surface  heated  to 
the  same  degree  with  that  given  by  our 
meridian  sun,  has  calculated,  that  the 
evaporation  from  the  Mediterranean  Sea 
in  a  summer's  day  is  5280  millions  of 
tons  of  water,  which  is  more  than  it  re- 
ceives from  all  the  nine  large  rivers  that 
empty  themselves  into  it.  Dr.  Watson, 
in  his  Chemical  Essays,  has  given  an  ac- 
count of  some  experiments  made  with  a 
view  to  determine  the  quantity  of  the  wa- 
ter raised  from  the  "earth  itself  alone  in 
time  of  drought.  He  informs  us,  that 
when  there  had  been  no  rain  for  above  a 
month,  and  the  grass  was  become  quite 
brown  and  parched,  the  evaporation  from 
an  acre  was  not  less  than  1600  gallons  in 
twenty-four  hours.  Making  afterwards 
two  experiments,  when  the  ground  had 
been  wetted  by  a  thunder-shower  the  day 
before,  the  one  gave  1973,  the  other  1905 
gallons,  in  twelve  hours.  From  this  the 
air  is  every  moment  purified  by  the 
ascent  of  the  vapour,  which,  flying  off  in- 


Atmosphere.  93 

to  the  clouds,  thus  leaves  room  for  the 
exhalation  of  fresh  quantities  ;  so  that  as 
the  vapour  is  considerably  lighter  than 
the  common  atmosphere,  and  in  conse- 
quence ascends  with  great  velocity,  the 
air  during  all  this  time  is  said  to  be  dry, 
notwithstanding  the  vast  quantity  of  aque- 
ous fluid  that  passes  through  it. 

In  the  physical  economy  also,  another 
provision  is  made  for  the  continual  reno- 
vation of  the  atmosphere.  Plants  derive 
subsistence  from  the  very  air  that  is  unfit 
for  animal  life,  and  in  return,  actually  emit 
that  vital  or  dephlogisticated  air,  upon  the 
enjoyment  of  which  the  latter  depends. 
Thus  we  see  a  constant  circulation  of 
benefits  maintained  between  the  two 
great  provinces  of  organized  nature.  The 
plant  purifies  what  the  animal  has  poison- 
ed ;  in  return,  the  contaminated  air  is 
more  than  ordinarily  nutritious  to  the 
plant.  Agitation  with  water  appears  to 
be  another  of  these  restoratives.  The 
foulesi  air  shaken  in  a  bottle  with  water 
for  a  sufficient  length  of  time,  recovers  a 
great  degree  of  its  purity.  Here,  then 
again,  allowing  for  the  scale  upon  which 
nature  works,  we  see  the  salutary  effects 
H2 


94  Atmosphere. 

of  storms  and  tempests.  The  yesty  waves, 
which  confound  the  heaven  and  the  sea, 
are  doing  the  very  thing  which  is  done 
in  the  bottle,  and  are  a  perpetual  scarce 
of  freshness  to  our  atmosphere. 

The  atmosphere,  as  we  have  seen, 
contains  a  great  deal  of  water,  together 
with  a  vast  heterogeneous  collection  of 
particles  raised  from  all  bodies  of  matter 
on  the  surface  of  the  earth,  by  effluvia,  ex- 
halations, &c.  so  that  it  may  be  consider- 
ed as  a  chaos  ©f  the  particles  of  all  sorts 
of  matter  confusedly  mingled  together. 
And  hence  the  atmosphere  has  been  con- 
sidered as  a  large  chemical  vessel,  in 
which  the  matter  of  all  kinds  of  subluna- 
ry bodies  is  copiously  floating  ;  and  thus 
exposed  to  the  continual  action  of  that 
immense  surface,  the  sun  ;  from  whence 
proceed  innumerable  operations,  subli- 
mations, separations,  compositions,  di- 
gestions,fermentations, putrefactions,  &c» 

There  is,  however,one  substance,  nam- 
ly,  the  electrical  fluid,  which  is  very  dis- 
tinguishable in  the  mass  of  the  atmos- 
phere. To  measure  the  absolute  quanti- 
ty of  this  fluid,  either  in  the  atmosphere, 
or  any  other  substance,  is  perhaps  impos- 


Atmosphere.  95 

sible  ;  and  all  that  we  know  on  this  sub- 
ject is  that  the  electric  fluid  pervades  the 
atmosphere  ;  that  it  appears  to  be  more 
abundant  in  the  superior  than  the  inferior 
regions  ;  that  it  seems  to  be  the  imme- 
diate bond  of  connection  between  the  at- 
mosphere and  the  water  which  is  suspen- 
ded in  it ;  and  that,  by  its  various  opera- 
tions, the  phenomena  of  the  meteors  are 
occasioned. 

It  is  the  opinion  of  the  most  celebrated 
philosophers  of  the  present  day,  that  the 
electric  fluid  is  no  other  than  the  light  of 
the  sun  ;  that  it  issues  from  that  lumina- 
ry in  the  pure  state  of  electricity,  that 
joining  the  particles  of  our  atmosphere,  it 
becomes  light,  and  uniting  with  the  gros- 
ser earth  Jire. — The  evaporation  of  wa- 
ter is  attended  with  an  absorption  of  this 
fluid  from  the 'surface  of  our  globe,  and, 
on  the  other  hand,  the  conversion  of 
steam  into  water,  is  attended  with  a  de- 
position of  this  subtle  fluid  ;  so  that  there 
is  a  circulation  in  the  electric  fluid  as 
there  is  in  the  water.  It  descends  origin- 
ally from  the  sun  ;  pervades  the  whole 
srubstance  of  the  globe  ;  and  perspiring, 
as  it  were,  at  every  pore,  ascends  beyond 


96  Atmosphere. 

the  clouds  ;  and,  passing  the  extreme 
boundaries  of  our  atmosphere,  returns  to 
the  sun  from  whence  it  came. 

The  uses  of  the  atmosphere  are  so  ma- 
ny and  great,  that  it  seems  indeed  abso- 
lutely necessary,  not  only  to  the  comfort 
and  convenience  of  men,  but  even  to  the 
existence  of  all  animal  and  vegetable  life, 
and  to  the  very  constitution  of  all  kinds 
of  matter  whatever,  and  without  which 
they  would  not  be  what  they  are  ;  for  by 
it  we  live,  breathe,  and  have  our  being  ; 
and  by  insinuating  itself  into  all  the  va- 
cuities of  bodies,  it  becomes  the  great 
spring  of  most  of  the  mutations  here  be- 
low, as  generation,corruption,dissolution, 
&c.  and  without  which  none  of  these  op- 
erations could  be  carried  on.  Without 
the  atmosphere,  no  animal  could  exist, 
or  indeed  be  produced;  neither  any  plant, 
all  vegetation  ceasing  without  its  aid  ; 
there  would  be  neither  rain  nor  dews  to 
moisten  the  face  of  the  ground :  and, 
though  we  might  perceive  the  sun  and 
stars  like  bright  specks,  we  should  be  in 
utter  darkness,  having  none  of  what  we 
call  day-light,  or  even  twilight:  nor  would 
either  fire  or  heat  exist  without  it.  In 


Atmosphere.  97 

short,  the  nature  and  constitution  of  all 
matter  would  be  changed  and  cease;  wan- 
ting this  universal  bond  and  constituting 
principle* 

As  to  the  weight  and  pressure  of  the 
air,  it  is  evident  that  the  mass  of  the  at- 
mosphere, in  common  with  all  other  mat- 
ter, must  be  endued  with  weight  and 
pressure  ;  and  this  principle  was  asserted 
by  almost  all  philosophers,  both  ancient 
and  modern.  But  it  was  only  by  means 
of  the  experiments  made  with  pumps  and 
the  barometrical  tube,  by  Galileo  and 
Torricelli,  that  we  came  to  the  proof,  not 
only  that  the  atmosphere  is  endued  with 
a  pressure,  but  also  what  the  measure 
and  quantity  of  that  pressure  is.  Thus  it 
is  found,  that  the  pressure  of  the  atmos- 
phere sustains  a  column  of  quicksilver,  in 
the  tube  of  the  barometer,  of  about  thirty 
inches  in  height :  it  therefore  follows, 
that  the  whole  pressure  of  the  atmosphere 
is  equal  to  the  weight  of  a  column  of  quick 
silver,  of  an  equal  base,  and  thirty  inches 
height:  and,  because  a  cubical  inch  of 
quicksilver  is  found  to  weigh  nearly  half 
a  pound  avoirdupois,  therefore  the  whole 
thirty  inches,  or  the  weight  of  the  atmosr 


98  Atmosphere. 

phere  on  every  square  inch  of  surface  is 
equal  to  15lb.  Again,  it  has  been  found 
that  the  pressure  of  the  atmosphere  bal- 
ances, in  the  case  of  pumps,  &c.  a  column 
of  water  of  about  3  |  feet  high  ;  and  the 
cubical  foot  of  water  weighing  just  100O 
ounces,  or  6~^.b.  34-|  times  62-|,  or  2158 
Ib.  will  be  the  weight  of  the  column  of 
water,  or  of  the  atmosphere,  on  a  base  of 
a  square  foot;  and  consequently  the  144th 
part  of  this,  or  15lb.  is  the  weight  of  the 
atmosphere  on  a  square  inch ;  the  same 
as  before.  Hence  Mr.  Cotes  computed, 
that  the  pressure  of  this  ambient  fluid  on 
the  whole  surface  of  the  earth,  is  equiva- 
lent to  that  of  a  globe  of  lead  of  sixty  miles 
in  diameter.  And  hence  also  it  appears, 
that  the  pressure  upon  the  human  body 
must  be  very  considerable ;  for  as  every 
square  inch  of  surface  sustains  a  pressure 
of  15lb.  every  square  foot  will  sustain  144 
times  as  much,  or  2160lb.  then,  if  the 
whole  surface  of  a  man's  body  be  suppo- 
sed to  contain  fifteen  square  feet,  which 
is  pretty  near  the  truth,  he  must  sustain 
15  times  2160,  or  32400lb.  that  is  near 
14-|  tons  weight  for  his  ordinary  load* 
By  this  enormous  pressure  we  should  un- 


Atmosphere.  98 

doubtedly  be  crushed  in  a  moment,  if  all 
parts  of  our  bodies  were  not  filled  either 
with  air  or  some  other  ela&tic  fluid,  the 
spring  of  which  is  just  sufficient  to  coun- 
terbalance the  weight  of  the  atmosphere,, 
But,  whatever  this  fluid  may  be,  it  is  cer- 
tain that  it  is  just  able  to  counteract  the 
weight  of  the  atmosphere,  and  no  more  : 
for  if  any  considerable  pressure  be  super- 
added  to  that  of  the  air,  as  by  going  into 
deep  water ,or  the  like,it  is  always  severe- 
ly felt,  let  it  be  ever  so  equable,  at  least 
when  the  change  is  made  suddenly  ;  and 
if,  on  the  other  hand,  the  pressure  of  the 
atmosphere  be  taken  off  from  any  part  of 
the  human  body,  as  the  hand  for  instance, 
when  put  over  an  open  receiver,  from 
whence  the  air  is  afterwards  extracted, 
the  weight  of  the  external  atmosphere 
then  prevails,  and  we  imagine  the  hand 
strongly  sucked  down  into  the  glass. 

The  difference  in  the  weight  of  the  air 
which  our  bodies  sustain  at  one  time 
more  than  another,  is  also  very  consider- 
able, from  the  natural  changes  in  the  state 
of  the  atmosphere.  This  change  takes 
place  chiefly  in  countries  at  some  distance 
from  the  equator  ;  and,  as  the  barometer 


10O  Atmosphere. 

varies  at  times  from  twenty-eight  to  thitv 
ty-one  inches,  or  about  one  tenth  of  the 
whole  quantity,  it  follows,  that  this  diffe- 
rence amounts  to  about  a  ton  and  a  half 
on  the  whole  body  of  a  man,  which  he 
therefore  sustains  at  one  time  more  than 
at  another.  On  the  increase  of  this  natu- 
ral weight,  the  weather  is  commonly  fine, 
and  we  feel  ourselves  what  we  call  braced, 
and  more  alert  and  active ;  but,  on  the 
contrary,  when  the  weight  of  the  air  di- 
minishes, the  weather  is  bad,  and  people 
feel  a  listlesness  and  inactivity  about 
them.  And  hence  it  is  no  wonder  that 
persons  suffer  very  much  in  their  health, 
from  such  changes  in  the  atmosphere  es- 
pecially when  they  take  place  very  sud- 
denly. 

The  weight  of  the  atmosphere  has  great 
influence  on  a  number  of  physical  pheno- 
mena. It  compresses  all  bodies,  and  op- 
poses their  dilatation.  It  is  an  obstacle 
to  the  evaporation  of  fluids.  The  water 
of  the  sea  is  by  this  cause  preserved  in  its 
liquid  state,  without  which  it  would  take 
the  vaporous  form,  as  we  see  in  the  vacu- 
um of  the  air  pump.  The  pressure  of 
the  air  on  our  bodies  preserves  the  state 


Atmosphere.  101 

both  of  the  solids  and  fluids  ;  and  from 
the  want  of  this  due  pressure  it  is  that  on 
the  summits  of  lofty  mountains  the  blood 
often  issues  from  the  pores  of  the  skin, 
or  from  the  lungs. 

Various  attempts  have  been  made  to 
ascertain  the  height  to  which  the  atmos- 
phere is  extended  all  round  the  earth. 
These  commenced  soon  after  it  was  dis- 
covered by  means  of  the  Torricellian  tube 
that  air  is  endued  with  weight  and  pres- 
sure. And  had  notthe  air  an  elastic  pow- 
er, but  were  it  every  where  of  the  same 
density,  from  the  surface  of  the  earth  to 
the  extreme  limit  of  the  atmosphere,  like 
water,  which  is  equally  dense  at  all  depths 
it  would  be  a  very  easy  matter  to  deter- 
mine its  height  from  its  density  and  the 
column  of  mercury  it  would  counterbal- 
ance in  the  barometer  tube  :  for,  it  having 
been  observed,  that  the  weight  of  the  at- 
mosphere is  equivalent  to  a  column  of 
thirty  inches  or  2-|  feet  of  quicksilver  and 
the  density  of  the  former  to  that  of  the 
latter,  as  1  to  1104O;  therefore  the  height 
of  the  uniform  atmosphere  would  be 
11040  times  2£  feet,  that  is,  27600  feet, 
or  little  more  than  5^  miles.  But  the  air, 
I 


102  Atmosphere.      , 

by  its  elastic  quality,  expands  and  con- 
tracts ;  and  it  being  found,  by  repeated 
experiments  in  most  nations  of  Europe, 
that  the  spaces  it  occupies,  when  compres- 
sed by  different  weights,  are  reciprocally 
.proportional  to  the  weights  themselves  ; 
or,  that  the  more  the  air  is  pressed,  so 
much  the  less  space  it  takes  up ;  it  follows 
that  the  air  in  the  upper  regions  of  the  at- 
mosphere must  grow  continually  more 
and  more  rare,  as  it  ascends  higher  ;  and 
indeed  that,  according  to  that  law,  it 
must  necessarily  be  extended  to  an  indef- 
inite height.  At  the  height  of  3-|  miles 
the  density  of  the  atmosphere  is  nearly  2 
times  rarer  than  it  is  at  the  surface  of  the 
earth ;  at  the  height  of  seven  miles,  4 
times  rarer ;  and  so  on,  according  to  thr 
following  table. 

Height  in  miles.  Number  of  times  rarer 

3* 2 

7 4 

14 16 

21 64  N 

28 256 

35 1024 

42 4096 

' 16384 


Atmosphere,,  105 

56 65536 

63 262144 

7O 1048576 

By  pursuing  these  calculations,  it 
might  be  easily  shewn,  that  a  cubic  inch  of 
the  air  we  breathe  would  be  so  much 
rarefied  at  the  height  of  500  miles,  that 
it  would  fill  a  sphere  equal  in  diameter  to 
the  orbit  of  Saturn.  Hence  we  may  per- 
ceive how  very  soon  the  air  becomes  so 
extremely  rare  and  light,  as  to  be  utterly 
imperceptible  to  all  experience  ;  and  that 
hence,  if  all  the  planets  have  such  atmos- 
pheres as  our  earth,  they  will,  at  the  dis- 
tances of  the  planets  from  one  another, 
be  so  extremely  attenuated,  as  to  give  no 
sensible  resistance  to  the  planets  in  their 
motion  round  the  sun  for  many,  perhaps 
hundreds  or  thousands  of  ages  to  come. 
Even  at  the  height  of  about  fifty  miles, 
it  is  so  rare  as  to  have  no  sensible  effect 
on  the  rays  of  light. 

Mr.  Boyle  in  his  physico-mechanical 
experiments  concerning  the  air,  declares 
it  probable  that  the  atmosphere  may  be 
several  hundred  miles  high  ;  which  is 
easy  to  be  admitted,  when  we  consider^ 
what  he  proves  in  another  part  of  the 


104  Atmosphere. 

same  treatise,  viz.  that  the  air  here 
about  the  surface  of  the  earth,  when  the 
pressure  is  taken  from  it,  dilates  into 
10,000,  and  even  at  last  into  13,679  times 
its  space  ;  and  this  altogether  by  its  own 
expansive  force,  without  the  help  of  fire. 
In  fact,  it  appears,  that  the  air  we  breathe 
is  compressed  by  its  own  \veight  into  at 
least  the  13,679th  part  of  the  space  it 
would  possess  in  vacua.  But,  if  the  same 
air  be  condensed  by  art,  the  space  it 
would  take  up  when  dilated,  to  that  it 
possesses  when  condensed,  will  be,  accor- 
ding to  the  same  author's  experiments, 
as  550.0OO  to  1. 

Our  direct  experiments,  however,  not 
reaching  to  any  great  heights  into  the  re- 
gions of  the  atmosphere,  and  not  know- 
ing how  far  air  may  be  expanded,  we  are 
incapable  of  determining  to  what  height 
the  atmosphere  is  actually  extended. 


Meteors.  105 

CHAP.  VII. 

Of  the  Meteors. 

WE  have  seen  that  the  atmosphere  is 
a  vast  laboratory,  in  which  nature  ope- 
rates immense  analyses,  solutions,  preci- 
pitations, and  combinations  ;  it  is  a  grand 
receiver,  in  which  all  the  attenuated,  vo- 
latilized productions  of  terrestrial  bodies 
are  received,  mingled,  agitated,  combined 
and  separated.  Considered  in  this  view, 
the  atmospheric  air  is  a  chaos,  an  inde- 
terminate mixture  of  mineral,  vegetable, 
and  animal  effluvia,  which  the  electric 
fluid  is  pervading  and  traversing  contin- 
ually. The  grand  changes  it  experiences, 
and  of  which  we  are  sensible  in  ex- 
tensive spaces  by  the  appearance  of  wa- 
ter, light,  or  noise,  are  called  meteors* 
As  the  state  of  the  atmosphere  is  ever 
varying,  the  meteors  assume  different 
forms  ;  some  delighting  us  with  their  ap- 
pearance, while  others  wear  a  terrifying 
12 


1O6  Meteors. 

aspect.  In  this  repository  is  collected 
the  gentle  dew  and  hoar-frost ;  here 
clouds  are  gathered  and  carried  along  by 
the  wind,  to  refresh  the  earth  in  falling 
showers,  give  rise  to  rivers,  spread  vast 
inundations  of  water  over  the  fields,  or 
lay  them  under  a  covering  of  snow  or 
hail ;  here  mock-suns,  mock-moons,  ha- 
loes, and  rainbows  make  their  gaudy  but 
transitory  appearance  ;  and  here  the  wa- 
ter-spout, dreadful  to  the  mariner  ;  here 
rolls  the  dreadful  thunder,  here  lightnings 
dart  their  vivid  flames,  and  sometimes, 
striking  upon  the  earth,  destroy  its  pro- 
ductions, fill  its  inhabitants  with  terror, 
and  sometimes  strike  them  dead ;  here 
the  auroras,  or  streamers,  the  ignesfatui, 
or  wandering  fires,  called  also  Jack  with 
the  Lantern ;  here  falling  stars,  as  they 
are  ignorantly  termed,  or  fiery  balls  of  va- 
rious sizes,  appear  with  splendour  during 
the  gloom  of  night,  and  astonish  man- 
kind, who  too  often  seem  willing,  with 
superstitious  awe,  to  find  portentous  o- 
mens  of  dire  calamities  in  these  curious 
phenomena,  rather  than  investigate  their 
causes  or  discover  their  uses. 


Meteors*  107 

To  account  for  these  various  appear- 
ances in  a  satisfactory  manner,  it  is  plain 
that  we  ought  to  have  an  intimate  ac- 
quaintance with  the  constitution  of  the  at- 
mosphere ;  with  the  nature  of  those  pow- 
erful agents  by  which  it  appears  to  be 
principally  influenced,  viz.  fire,  light, 
and  electric  fluid  ;  and  with  their  peculiar 
modes  of  operation  and  action  upon  one 
another  and  upon  the  atmosphere,  and 
this  in  every  possible  variety  of  circum- 
stances. Nor  is  even  all  this  sufficient : 
the  various  phenomena  of  rain,  wind, 
snow,  thunder,  heat,  cold,  &c.  are  known 
to  depend  very  much  upon  the  situation 
of  different  places  on  the  surface  of  the 
earth  ;  and  the  occasional  variations  are 
with  great  reason  suspected  to  proceed, 
partly  at  least,  from  changes  which  take 
place  in  the  bowels  of  the  earth  :  whence 
we  ought  not  only  to  be  perfectly  well  ac- 
quainted with  geography,  but  with  mine- 
ralogy also:  and  that  to  an  extent  at  which 
human  knowledge  will  probably  never 
arrive. 

In  a  subject  so  very  difficult,  it  is  not  to 
be  'supposed  that  any  thing  like  a  certain 
and  established  theory  can  be  laid  down 


108  Meteors. 

in  this  little  elementary  work.  As  eva- 
poration, however,  seems  particularly  to 
be  concerned  in  the  production  of  the  me- 
teors, we  shall  take  a  view  of  that  opera- 
tion of  nature,  the  extent  of  which  we 
have  noticed  in  the  preceding  chapter. 
This  process  may  be  reckoned  in  a  par- 
ticular manner  the  effect  of  heat.  Upon 
this  principle  vapour  is  shown  to  be  a 
compound  of  water  and  fire  ;  and  such  it 
is  supposed  to  be  by  philosophers  of  the 
highest  rank.  In  considering  this  opera- 
tion, however,  as  carried  on  by  nature, 
we  shall  soon  find,  that  it  proceeds  in  a 
manner  very  different  from  what  takes 
place  in  our  chemical  operations.  In  the 
latter,  evaporation  is  merely  the  effect  of 
heat;  and  the  process  cannot  go  on  with- 
out a  considerable  degree  of  it.  In  the 
natural  way,  on  the  contrary,  the  process 
goes  on  under  almost  every  degree  of  cold 
we  know  ;  the  vapours  ascend  to  a  height 
which  has  never  yet  been  determined  ; 
and,  from  the  extreme  cold  which  they 
sustain,  show  evidently  that  they  are  con- 
nected with  our  atmosphere  by  mrans  of 
some  other  agent  besides  heat.  From  the 
continual  ascent  of  vapour  indeed,  if  the 


Meteors.  109 

operations  of  nature  were  of  the  same 
kind  with  those  of  art,  the  upper  parts  of 
our  atmosphere  would  be  always  involved 
in  a  fog,  by  reason  of  the  condensation 
of  the  vast  quantity  which  continually  as- 
cends thither :  but  so  far  is  this  from  be- 
ing the  case,  that  in  those  elevated  regions 
to  which  the  vapours  continually  ascend, 
the  air  is  much  drier  than  at  the  surface 
of  the  ground. 

From  many  experiments,  indeed,  it  is 
evident,  that  water,  after  being  reduced 
into  a  state  of  vapour,  is  capable  of  un- 
dergoing a  certain  change,  by  which  it 
lays  aside  its  fluidity  entirely,  and  even 
to  appearance  its  specific  gravity ;  so 
that  it  becomes,  as  far  as  we  can  judge,  a 
substance  totally  different  from  what  it 
was  before.  After  water  has  attained  to 
this  state,  our  inquiries  concerning  it 
must  in  a  great  measure  cease  ;  but  as  it 
is  not  in  the  immediate  product  of  evapo- 
ration that  rain  has  its  source,  and  as  va- 
pours change  their  nature  in  the  atmos- 
phere, so  as  to  be  no  longer  sensible  to  the 
hygrometer  or  to  the  eye,  and  do  not  be- 
come vapour  again  till  clouds  appear,  we 
must  acknowledge  it  to  be  very  probable, 


110  Meteors. 

that  the  intermediate  state  of  vapour  is  no 
other  than  air  ;  and  that  the  clouds  do  not 
proceed  from  any  distinct  fluid  in  the  at- 
mosphere, but  from  a  decomposition  of  a 
part  of  the  air  itself,  perfectly  similar  to 
the  rest. 

Granting  this  to  be  the  case,  and  we 
can  scarcely  hope  for  a  more  probable 
conjecture  on  the  subject,  the  decompo- 
sition of  the  vapour  will  be  easily  accoun- 
ted for.  If  by  any  natural  process  the 
water  can  be  con  verted  into  air,  and  if  the 
latter  is  only  water  partially  decomposed; 
then,  by  an  inversion  of  the  process,  air 
may  be  instantly  re-converted  into  water, 
and  will  become  visible  in  fog  or  mist, 
or  be  condensed  into  rain,  consisting  of 
greater  or  smaller  drops,  according  to 
the  degree  to  which  this  inverted  process 
is  carried. 

It  is  generally  supposed  by  meteorolo- 
gists, from  all  the  clouds,  fogs,  hail,  rain, 
and  snow,  being  electrified,  that  the  elec- 
tric fluid  is  the  agent  employed  in  the  for- 
mation of  these  meteors,  and  that  it  is  this 
fluid  which  acts  in  the  re-conversion  of 
air  into  water.  This  process  may  be  par- 
ticularly observed  in  the  summer  season, 


Meteors.  1 1 1 

when  the  horizon  is  suddenly  overcast, 
and  a  copious  torrent  of  rain  ensues,  which 
cannot  be  from  the  rising  of  any  aqueous 
vapours  at  the  time,  but  must  be  from  a 
precipitation  of  water  that  existed  in  an 
invisible  state  in  the  atmosphere. 

Water  may  therefore  exist  in  air  ;  1st, 
in  an  invisible  state,  which  is  the  case  when 
the  dissolving  power  of  air  is  considera- 
ble ;  2dly,  in  a  state  of  incipient  separa- 
tion, in  which  case  it  forms  clouds,  mists  ^ 
or  fogs  ;  3dly,  and  lastly,  in  a  state  of  ac- 
tual separation,  in  which  case  it  forms  ei- 
ther rain,  properly  so  called,  or  snow,  or 
hail. 

Clouds  are  those  well  known  assembla- 
ges of  vapours  that  float  in  the  atmosphere, 
have  different  degrees  of  opacity,  which 
arise  from  their  extent  and  density,  and 
generally  have  pretty  well  defined  boun- 
daries. Their  height  above  the  surface 
of  the  earth  (we  mean  not  above  the  moun- 
tains) is  various,  but  hardly  ever  exceeds 
a  mile  or  a  mile  and  a  half.  In  hot  wea- 
ther, or  hot  climates,  the  clouds,  being 
more  rarefied,  are  lighter,  and  ascend 
much  higher  than  they  do  in  colder  cli- 
mates, or  colder  weather  :  and  indeed,  in 


112  Meteors. 

cold  weather  the  clouds  frequently  touch 
the  very  surface  of  the  earth  ;  for  a  fog 
may  with  propriety  be  called  a  cloud  close 
to  the  ground. 

A  mist  is  a  very  indefinite  word.  It 
means  an  incipient  formation  of  clouds, 
or  haziness  ;  and  it  often  denotes  a  very 
small  rain,  or  deposition  of  water  in  par- 
ticles so  small  as  not  to  be  visible  singly. 

The  snow  is  formed  when  the  atmos- 
phere is  so  cold  as  to  freeze  the  particles 
of  rain  as  soon  as  they  are  formed,  and 
the  adherence  of  several  of  those  parti- 
cles to  each  other,  which  meet  and  cling 
to  each  other  as  they  descend  through 
the  air,  forms  the  usual  fleeces  of  snow, 
which  are  larger,  (since  they  are  longer 
in  descending,  and  have  a  greater  oppor- 
tunity of  meeting)  when  the  clouds  are 
higher  than  when  they  are  lower. 

The  hail  differs  from  snow  in  its  con- 
sisting of  much  more  solid,  and  much 
more  dehned  pieces  of  congealed  water. 
It  is  sui  posed  that  the  water,  already 
formed  into  considerable  drops,  is  driv- 
en and  detained  a  considerable  time 
through  a  cold  region  of  the  atmosphere, 
by  the  wind,  which  almost  always  accom- 


Meteors.  113 

panics  a  fall  of  hail.  But  the  globes  of 
ice,  or  hail-stones,  in  a  fall  of  hail,  some- 
times far  exceed  the  usual  size  of  the 
'drops  of  rain  ;  which  shews  that  by  the 
action  of  the  wind,  the  congealed  parti- 
cles must  be  forced  to  adhere  to  each  oth- 
er ;  and,  in  fact,  though  the  small  hail- 
stones are  more  uniformly  solid  and  glo- 
bular, the  large  ones  almost  always  con- 
sist of  a  harder  nucleus,  which  is  sur- 
rounded by  a  softer  substance,  and  some- 
times by  various  distinct  pieces  of  icet 
just  agglutinated.  Their  shape  is  sel- 
dom perfectly  globular. 

The  phenomena  of  dew  and  hoar-frost 
seem  to  proceed  from  a  quantity  of  aque- 
ous and  undecomposed  vapour  which 
always  exists  in  the  atmosphere  ;  and 
which,  being  raised  by  mere  heat,  is  con- 
densed by  mere  cold,  without  undergo- 
ing that  process  by  which  water  is  chan- 
ged into  air. 

If  the  cold  be  very  intense,  hoar-frost 
appears  instead  of  dew  ;  which  is  nothing 
more  than  the  dew  frozen  after  it  falls 
upon  the  ground,  in  the  same  manner 
that  the  vapour  in  a  warm  room  congeals 
on  the  inside  of  the  windpws  in  a  frosty 
night.  K 


Meteors. 

Lightning  is  found  to  be  a  flash,  pro- 
duced by  the  electrical  fluid  rush  ing  from? 
one  part  into  another  ;  and  thunder  the 
sound  of  the  rushing  torrent,  reverbera- 
ted among  the  clouds.  The  aurora  bo- 
•realis,  or  northern  dawn,  is  likewise  an 
electrical  phenomenon.  It  is  a  lambent 
or  flashing  light,  seen  at  night  in  some 
periods  more  often  than  in  others,  espe- 
cially about  the  poles.  The  fery -balls, 
\vhich  are  seen  shooting  through  the  at- 
mosphere in  the  night,  of  various  magni- 
tudes and  of  different  forms,  seem  all  to 
rise  from  inflammable  vapours,  taking 
lire  from  their  fermenting,  or  effervescing 
in  the  air. 

The  Rainbotv  is  one  of  the  most  sur- 
prising of  the  works  of  God,  which  the 
Hebrews  called  the  bow  of  God,  and  the 
Greeks  the  Daughter  of  Wonder.  This 
phenomenon  is  seen  in  the  falling  rain  or 
dew,  and  not  in  the  cloud  whence  that 
rain  or  dew  proceeds  ;  it  is  caused  by  a 
reflection  and  refraction  of  the  sun's  rays 
from  the  globular  particles  of  rain.  The 
face  of  this  beautiful  iris,  or  bow,  is  ting- 
ed with  all  the  primogenial  colours  in 
iheir  natural  order;  viz*  violet^  indigo •, 


Meteors.  115 

green,  yellow  and  red.  It  always 
appears  in  that  part  of  the  heavens  oppo- 
site the  sun. 

The  Halos,  are  circles  somewhat  akin 
to  the  rainbow,  which  appear  about  the 
sun  and  moon,and  are  sometimes  various- 
ly coloured.  They  never  appear  in  a 
rainy  sky,  but  in  a  rimy  and  frosty  one* 
and  are  formed  by  the  refraction  of  the 
rays  of  light,  without  any  reflection  as  in 
the  rainbow* 

Mo.ck-suns  and  mock-moons  are  repre- 
sentations of  the  face  of  the  true  sun  an.d. 
moon  by  reflection  in  the  clouds. 

The  weight  and  pressure  of  the  atmos- 
pherical air  have  been  explained  in  the 
preceding  chapter.  We  shall  now  exam- 
ine the  particulars  relative  to  its  progres- 
sive motion,  which  we  denominate  wind* 

Wind  is  a  stream  or  current  of  air  ;  as 
the  air  is  a  fluid,  its  natural  state  is  that 
of  rest,  which  it  endeavours  always  to 
keep  or  retrieve  by  an  universal  equilibri- 
um of  all  its  parts.  When,  therefore,  this 
natural  equilibrium  of  the  atmosphere 
happens  by  any  means  to  be  destroyed  in 
any  part,  there  necessarily  follows  a  mo- 


116.  Meteors* 

tion  of  all  the  circumjacent  air  towards 
that  part  to  restore  it ;  and  this  motion 
of  the  air  is  what  we  call  whid. 

Hence,  with  respect  to  that  place  where 
the  equilibrium  of  the  air  is  disturbed,  we 
see  the  wind  may  blow  from  every  point 
of  the  compass  at  the  same  time;  and  those 
who  live  northwards  of  that  point  have  a 
north  wind  ;  those  who  live  southwards, 
a  south  wind  ;  and  so  of  the  rest :  But 
those  who  live  on  the  spot,  where  all  these 
winds  meet  and  interfere,  are  oppressed 
with  turbulent  and  boisterous  weather, 
whirlwinds  and  hurricanes  ;  with  rain, 
tempest,  lightning,  thunder,  &c. 

Many  are  the  particular  causes  which 
produce  winH  by  interrupting  the  equi- 
poise of  the  atmosphere  ;  but  the  most 
general  causes  are  two,  viz.  heat,  which, 
by  rarefying  the  air,  makes  it  lighter  in 
some  places  than  it  is  in  others  ;  and  cold 
which,  by  condensing  it,  makes  it  heavier. 
Hence  it  is,  that  in  all  parts  over  the  tor- 
rid zone,  the  air  being  more  rarefied  by 
3  greater  quantity  of  the  solar  rays,  is 
much  lighter  than  in  the  other  parts  of  the 
atmosphere,  and  most  of  all  over  the 
equatorial  parts  of  the  earth.  And  since 


Meteors.  117 

trie  parts  at  the  equator  are  most  rarefied 
which  are  near  the  sun  ;  and  those  parts 
are,  by  the  earth's  diurnal  rotation  east- 
ward, continually  shifting  to  the  west ;  it 
follows,  that  the  parts  of  the  air  which  lie 
on  the  west  side  of  the  point  of  greatest 
rarefaction,  and,  by  flowing  towards  it, 
meet  it,  have  less  motion  than  those  parts 
on  the  east  of  the  said  point,  which  follow 
it ;  and  therefore  the  motion  of  the  east- 
ern air  would  prevail  against  that  of  the 
western  air,  and  so  generate  a  continual 
east  wind,  if  this  were  all  the  effect  of  that 
rarefaction.  But  we  are  to  consider  that 
as  all  the  parts  of  the  atmosphere  are  so 
greatly  rarefied  over  the  equator,  and  all 
about  the  poles  greatly  condensed  by  ex- 
treme cold,  this  heavier  air  from  either 
pole  is  constantly  flowing  towards  the 
equator,  to  restore  the  balance  destroyed 
by  the  rarefaction  and  levity  of  the  air  ov- 
er those  regions  ;  hence,  in  this  respect 
alone,  a  constant  north  and  south  wind 
would  be  generated. 

Now  it  is  easy  to  understand,  that  by  a 

composition  of  these  two  directions  of  the 

air  from  the  east  and  north,  a  constant 

north-east  wind  will  be  generated  in  the 

K2 


118  Meteors. 

northern  he  mi  sphere, and  a  constant  south- 
east wind  in  the  southern  hemisphere,  to 
a  certain  distance  on  each  side  the  equa- 
tor, all  round  the  earth.  And  this  case  we 
find  to  be  verified  in  the  general  trade 
-winds)  which  constantly  blow  from  the 
north-east  and  south-east,  to  about  thirty 
degrees  on  each  side  the  equator,  where 
those  parts  are  over  the  open  ocean,  and 
not  affected  with  the  reflection  of  the  sun- 
beams from  the  heated  surface  of  the  land, 
for  in  this  case  the  wind  will  always  set 
in  upon  the  land,  as  on  the  coast  of  Guin- 
ea, and  other  parts  of  the  torrid  zone,  we 
know  it  does. 

The  temperature  of  a  country  with  res- 
pect to  heat  or  cold,  is  increased  or  dim- 
inished by  winds,  according  as  they  come 
from  a  hotter  or  colder  part  of  the  world. 
The  north  and  north-easterly  winds,  in 
this  country  and  all  the  western  parts  of 
Europe,  are  reckoned  cold  and  drying 
winds.  They  are  cold  because  they  come 
from  the  frozen  region  of  the  north  pole, 
or  over  a  great  tract  of  cold  land.  Their 
drying  quality  is  derived  from  their  co- 
ming principally  over  land,"*  and  from  a 

*  This  is  not  true  with  regard  to  the  United  States ;  for  here 
the  north-east  wind,  coming  over  the  ocean,  instead  of  land, 
brirtjjs  along  with  it  so  great  a  degree  of  humidity  as  always 


Meteors.  119 

well  known  property  of  the  air,  namely, 
that  warm  air  can  dissolve,  and  keep  dis- 
solved, a  greater  quantity  of  water  than 
colder  air :  hence  the  air  which  comes 
from  colder  regions  being  heated  over 
warmer  countries,  becomes  a  better  sol- 
vent of  moisture,  and  dries  up  with  great 
energy  the  moist  bodies  it  comes  in  con- 
tact with  ;  and,  on  the  other  hand,  warm 
air  coining  into  a  colder  region  deposits 
a  quantity  of  the  water  it  kept  in  solution 
and  occasions  mists,  fogs,clouds,rains,&:c. 
In  warm  countries  sometimes  the  winds 
which  blow  over  a  great  tract  of  highly 
heated  land,  become  so  very  drying, 
scorching  and  suffocating,  as  to  produce 
dreadful  effects.  These  winds  under  the 
name  ofsolanos,  are  often  felt  in  the  des- 
erts of  Arabia,  in  the  neighbourhood  of 
the  Persian  gulph,  in  the  interior  of  Af- 
rica, and  in  some  other  places.  There  are 
likewise  in  India,  part  of  China,  part  of 
Africa,  and  else  where,  other  winds,  which 
deposit  so  much  warm  moisture  as  to  sof- 
ten, and  actually  to  dissolve  glue,  salts, 
and  almost  every  article  which  is  soluble 
in  water. 

to  produce  rain  or  snow,  according  to  the  temperature  of  the 
air ;  whereas,  as  here  stated,  in  Europe  the  same  wind  bio  wine; 
over  land,  it  always  produces  dry,  fair  weather. 


120  Meteors. 

It  is  impossible  to  give  any  adequate 
account  of  irregular  winds,  especially  of 
those  sudden  and  violent  gusts  which  come 
on  at  very  irregular  periods,  and  generally 
continue  for  a  short  time.  They  some- 
times spread  over  an  extensive  tract  of 
country,  and  at  other  times  are  confined 
within  a  remarkably  narrow  space.  Their 
causes  are  by  no  means  rightly  understood 
though  they  have  been  vaguely  attributed 
to  peculiar  rarefactions,  to  the  combined 
attractions  of  the  sun  and  moon,  to  earth- 
quakes, to  electricity,  £^c.  They  are 
called  in  general  hurricanes,  or  they  are 
the  principal  phenomenon  of  a  hurricane, 
that  is,  of  a  violent  storm. 

Almost  every  one  of  those  violent 
winds  is  attended  with  particular  pheno- 
mena, such  as  droughts  or  heavy  rains,  or 
hail,  or  snow,  or  thunder  and  lightning, 
or  several  of  those  phenomena  at  once. 
They  frequently  shift  suddenly  from  one 
quarter  of  the  horizon  to  another,  and 
then  come  again  to  the  former  point. 
In  this  case  they  are  called  tornadoes. 

Iu  some  parts  of  the  Indian  ocean 
there  are  winds  which  blow  one  way  du- 
ring one  half  of  the  year,  and  then  blow 
the  contrary  way  during  the  other  half 


Aleteor*.  121 

of  the  year.  These  winds  are  called 
monsoons,  and  owe  their  origin  to  causes 
similar  to  what  has  been  pointed  out. 

When  the  gusts  of  wind  come  from 
different  quarters  at  the  same  time,  and 
meet  in  a  certain  place,  there  the  air  ac- 
quires a  circular,  or  rotatory,  or  screw- 
like  motion,  either  ascending  or  descend- 
ing, as  it  were,  round  an  axis,  and  this 
axis  sometimes  is  stationary,  and  at  other 
times  moves  on,  in  a  particular  direction. 
This  phenomenon,  which  is  called  a 
whirlwind,  gives  a  whirling  motion  to 
dust,  sand,  water,  part  of  a  cloud,  and 
sometimes  even  to  bodies  of  great  weight 
and  bulk  ;  carrying  them  either  upwards 
or  downwards,  and  lastly  scatters  them 
about  in  different  directions. 

The  water-spout  has  been  attributed 
principally,  if  not  entirely,  to  the  meeting 
of  different  winds.  In  that  case  the  air 
in  its  rotation  acquires  a  centrifugal  mo- 
tion ;  whence  it  endeavours  to  recede 
from  the  axis  of  the  whirl,  in  conse- 
quence of  which  a  vacuum,  or,  at  least  a 
considerable  rarefaction  of  air,  takes  place 
about  the  axis,  and,  when  the  whirl  takes 
place  at  sea,  or  upon  water,  the  water  ri- 


122  Meteors. 

ses  into  that  rarefied  place ;  for  the 
same  reason  which  causes  it  to  ascend  in- 
to the  exhausted  tube,  and  forms  the 
water-spout  or  pillar  of  water  in  the  air. 
The  water-spouts  generally  break  about 
their  middle,  and  the  falling  waters  oc- 
casion great  damage,  either  to  ships  that 
have  the  misfortune  of  being  under  them, 
or  to  the  adjoining  land  ;  for  such  spouts 
are  sometimes  formed  on  a  lake,  or  river, 
or  on  the  sea  close  to  the  land. 

As  the  motion  of  the  air  has  a  greater 
or  lesser  velocity,  the  wind  is  stronger  or 
weaker  ;  and  it  is  found  from  observation, 
that  the  velocity  of  the  wind  is  various, 
from  the  rate  of  1  to  1OO  miles  per  hour. 
The  following  particulars  respecting 
the  velocity,  &?<:.  of  the  wind  are  extracted 
from  a  table  which  appeared  in  the  51st 
volume  of  the  Philosophical  Transactions, 
by  Mr.  J.  Smeaton,  the  celebrated  engi- 
neer.— 

When  the  velocity  of  the  wind  is  one 
mile  per  hour  it  is  hardly  perceptible. 
From  2  to  3  just  perceptible. 

4  —  5  gentle  pleasant  wind,  or  breezes, 

10  — 15  pleasant  brisk  gale. 

20  —25  very  brisk. 

30  —35  high  winds. 


Meteors*  120 

40 — 45  very  high. 

50  miles  per  hour  a  storm  or  tempest, 

60 a  great  storm. 

80 a  hurrscane. 

JQQ  C  a  hurricane  that  tears  up  trees 

'    \  carries  buildings  before  it,  8cc, 

The  winds  are  of  immense  and  indis- 
pensable use.  Besides  their  more  ob- 
vious effects  in  driving  of  ships,  wind- 
mills, &Pc.  they  preserve,  by  mixing, 
the  necessary  purity  of  the  air.  The 
winds,  likewise  drive  away  vapours, 
clouds  fogs,  and  mists  from  those  parts 
in  which  they  are  copiously  formed,  to 
others  which  are  in  want  of  moisture  ; 
and  thus  the  whole  surface  of  the  earth 
is  supplied  with  water.  It  is  the  winds 
which  diminish  the  heat,  and  augment  the 
moisture  of  the  torrid  zone,  and  produce 
contrary  effects  on  those  of  the  polar  re- 
gions, so  as  to  render  those  districts  of 
the  globe,  which  the  ancients  deemed 
totally  unfit  for  the  abode  of  man,  and 
other  animals,  by  reason  of  excessive 
heat,  not  only  habitable,  but  salutary  and 
pleasing  to  man  and  beast,  and  yielding 
great  variety  and  abundance  of  the 
choice  productions  of  nature* 


124     Springs )  Rivers ,  and  the  Seat, 


CHAP.  VIII. 

Of  Springs,  RiverSy  and  the  Sea. 

HAVING  viewed  water  as  it  takes  its 
departure  from  the  bosom  of  the  deep 
and  forms  the  watery  meteors,  we  shall 
now  survey  it  as  it  rises  in  the  salient 
spring,  and  gives  birth  to  the  gurgling 
rill,  or  uniting,  gives  coolness  to  the  land- 
scape in  the  magnificent  stream,  that  irl 
its  ample  range  fertilizes  its  neighbour- 
hood. 

Various  have  been  the  theories,  or 
rather  hypotheses  relating  to  the  origin 
of  springs  ;  but  it  seems  the  general  o- 
pinion  of  those  who  have  made  this 
branch  of  natural  philosophy  their  study, 
that  the  true  principles  which  supply  the 
waters  of  fountains  or  springs,  are  mel- 
ted snow,  rain  water,  and  condensed  va*- 
pours. 


Springs,  Rivers,  and  the  Sea*     i2£ 

The  prodigious  quantity  of  vapours 
raised  by  the  sun's  heat,  and  otherwise, 
being  carried  by  the  winds  over  the  low 
lands  to  the  very  ridges  of  mountains,  as 
the  Pyrenean,  the  Alps,  the  Apennine,  the 
Carpathian,  in  Europe ;  the  Taurus  the 
Caucasus,  Imaus  and  others  in  Asia ; 
Atlas  the  Monies  Lunce,  or  mountains 
of  the  moon,  with  other  unknown  ridges 
in  Africa ;  the  vapours  being  compelled 
by  the  stream  of  air  to  mount  up  with  it 
to  the  top  of  those  mountains,  where  the 
air  becoming  too  light  to  sustain  them, 
and  condensed  by  cold  they  strike  against 
their  summits^  which  causes  an  union  of 
their  particles,  and  are  precipitated  in 
water,  which  gleets  down  by  the  crannies 
of  the  stone  ;  and  entering  into  the  ca- 
verns of  the  hills,  gathers,  as  in  an  alem~ 
lie,  into  the  basons  of  stone  it  finds, 
which  being  once  filled,  all  the  overplus 
of  water  that  comes  thither,  runs  over  by 
the  lowest  places,  and  breaking  out  by 
the  sides  of  the  hills  forms  single  spmgs. 

Many  of  these  springs  running  down 

by  the  vallies,  between  the  ridges  of  the 

hills,  and   coming  to   unite,  form  little 

rivulets,  or  brooks  ;  many  of  these  agaia 

JL 


1 26     Springs,  Rivers,  and  the  Sea. 

meeting  in  one  common  valley,  and  gam- 
ing the  plain  ground,  being  grown  less 
rapid,  become  a  river;  and  many  of 
these  being  united  in  one  common  chan- 
nel, make  such  enormous  streams  as  the 
Rhine,  the  Rhone  and  the  Danube. 
And  it  may  almost  pass  for  a  rule,  that 
the  magnitude  of  a  river,  or  the  quantity 
of  water  it  discharges,  is  proportional  to 
the  length  and  heights  of  these  very 
ridges  from  whence  the  fountains  arise. 

The  several  sorts  of  springs  observed 
are  common  springs,  which  either  run 
continually,  and  then  they  are  called 
perennial  springs  ;  or  else  run  only  for  a 
time,  or  at  certain  times  of  the  year,  and 
then  they  are  called  temporary  springs. 
Intermitting  springs,  or  such  as  flow 
and  then  stop,  and  flow  and  stop  again, 
by  regular  alternations  or  intermissions, 
Reciprocating  springs,  whose  wraters  rise 
and  fall,  or  flow  and  ebb,  by  regular  in- 
tervals, or  reciprocations  of  the  surface. 

If  those  reservoirs  of  water  in  the  bo- 
dy of  mountains  be  situated  where  min- 
eral ores  abound,  or  the  ducts  or  feeding 
streams  run  through  mineral  earth,  it  is 
easy  to  conceive  the  particles  of  metal 


Springs,  Rivers-^  and  the  Sea.     127 

will  mix  with,  and  be  absorbed  by  the 
water,  which  being  saturated  therewith, 
becomes  a  mineral  spring  or  well.  If 
salt,  sulphur,  and  lime-stone  abound  in 
the  strata  through  which  the  water  pas- 
ses, it  will  then  be  saline,  sulphureous, 
and  lime-water.  If  sulphur  and  iron 
should  both  4  abound  in  the  parts  of  the 
hill,  whence  the  waters  come,  the  waters 
will  partake  of  the  warmth  or  heat, 
which  is.  occasioned  by  the  mixture  of 
two  such  substances  in  the  earth,  where 
they  are  found. 

Having  noticed  the  different  kinds  of 
springs,  we  shall  say  a  few  words  respec- 
ting the  various  phenomena  which  take 
place  in  rivers. 

A  large  collection  of  water  which  runs 
in  consequence  of  its  gravity  from  at 
higher  to  a  lower  pare  of  the  surface  of 
the  earth,  in  a  channel  generally  open  at 
top,  is  called  a  river. 

A  river  which  flows  uniformly,  and 
preserves  the  same  height  in  the  sa-ne 
place,  is  said  to  be  in  a  permanent  state  ; 
such  rivers  are  very  rare. 

The  water  of  a  river  does  not  flow 
with  the  same  velocity  through  the 


128     Springs,  Rivers,  and  the  Sea. 

whole  width  of  the  river.  The  line  in 
which  the  water  moves  with  the  greatest 
velocity  is  called  the  thread  of  the  river, 
and  this  thread  seldom  lies  in  the  middle 
of  the  river,  but  it  generally  comes  near- 
er to  one  side  than  the  other,  according 
to  the  nature  of  the  impediments,  and 
the  configuration  of  the  banks.  The  ve- 
locity of  rivers  is  likewise  less  at  the 
bottom  of  their  channels,  than  at  their 
surface  ;  owing  to  the  resistance  which 
the  bed  makes  to  the  water  as  it  flows. 

The  running  of  rivers  is  upon  the  same 
principle  as  the  descent  of  bodies  on  in- 
clined planes  ;  for  water  no  more  than  a 
solid  can  move  on  a  horizontal  plane,  the 
re-action  of  such  a  plane  being  equal  and 
contrary  to  gravity  entirely  destroys  it, 
and  leaves  the  body  at  rest;  here  we  speak 
of  a  plane  of  small  extent,  and  such  as  co- 
incides with  the  curved  surface  of  the 
earth.  But  if  we  consider  a  large  extent 
or  long  course  of  water,  then  we  shall  find 
that  such  water  can  never  be  at  rest  but 
when  the  bottom  of  the  channel  coincides 
every  where  with  the  curved  surface  of 
the  earth.  In  rivers  that  are  made  it  is 
usual  to  allow  the  fall  of  1  foot  in  300,  but 


Springs,  Rivers,  and  the  Sea.     129 

the  declivity  of  those  formed  by  nature  is 
\rarious  and  uncertain. 

The  velocity  of  the  water  of  a  river 
Ottght  to  increase  in  proportion  as  it  re- 
cedes from  its  source  :  but  the  numerous 
causes  of  retardation,  which  occur  in  riv- 
ers, are  productive  of  very  great  irregu- 
larities ;  and  it  is  impossible  to  form  any 
general  rules  for  determining  such 
irregularities. 

The  unequal  quantities  of  water  (ari- 
sing from  rains,  from  the  melting  of  snow 
&c.)  which  are  conveyed  by  rivers  at  dif- 
ferent seasons,  enlarge  or  contract  their 
widths,  render  them  more  or  less  rapid, 
and  change  more  or  less  the  form  of  their 
beds.  But  independent  of  this,  the  size 
and  form  of  a  river  is  liable  to  be  continu- 
ally altered  by  the  usual  flowing  of  its 
waters,  and  by  local  peculiarities.  The 
water  constantly  corrodes  its  bed  where- 
ver it  runs  with  considerable  velocity, 
and  rubs  off  the  sand,  or  other  not  very 
coherent  parts.  The  corrosion  is  most 
remarkable  in  that  part  of  the  bottom, 
which  is  under  the  thread 'of  the  river,  or 
where  the  water  descends  suddenly  from 
an  eminence,  as  in  a  cascade  or  water -fall* 
L2 


1 3O    Springs ,  Rivers,  and  the  Sea. 

The  sand  thus  raised  is  deposited  in  pla- 
ces where  the  water  slacks  its  velocity, 
and  there  by  degrees  an  obstacle,  a  bank, 
and  even  an  island,  is  formed,  which  in 
its  turn  produces  other  changes.  Thus  a 
river  sometimes  forms  itself  a  new  bed, 
or  it  oversows  the  adjacent  grounds.  k 

In  some  places  we  find  that  an  obstacle 
or  a  bent  on  one  side  will  occasion  a  cor- 
rosion on  the  opposite  bank,  by  directing 
the  impetus  of  the  stream  towards  that 
bank. — Thus,  from  divers  causes,  whose 
concurrence  in  different  proportions,  and 
at  different  times,  forms  an  infinite  varie- 
ty, the  velocity  of  rivers  is  never  steady 
or  uniform. 

The  following  curious  calculation  res- 
pecting the  river  Thames  was  made  by  Dr 
Halley. "  In  order  to  estimate  the  quanti- 
ty of  water,  which  passes  daily  through 
the  Thames,  the  Doctor  assumes  the 
breadth  of  the  river  at  Kingston  bridge, 
(where  the  flood  seldom  reaches)  to  be 
100  yards,  and  the  depth  3  ;  so  that  the 
section  of  the  channel  is  300  square  yards, 
and  allowing  the  velocity  of  the  \vater  to 
be  at  the  rate  of  2  miles  per  hour,  there 
will  run  in  24  hours,  the  length  of  48  miles 


Springs,  Rivers,  and  the  Sea.     131 

or  84480  yards  ;  therefore  84480  x  SOOzz 
25,344,000  cubic  yards,  which  make  203,- 
000,000  tons  which  the  river  Thames 
yields  per  diem. 

The  proportional  lengths  of  course  of 
some  of  the  most  noted  rivers  in  the  world 
are  shewn  nearly  by  the  following  num- 
bers, extracted  from  Mr.  RennelPs  paper 
71st  vol.  Phil.  Trans. 

European  Rivers. 

Thames 1 

Rhine 5~ 

Danube 7 

Wolga 9| 

Asiatic  Rivers. 

Indus 5^ 

Euphrates .  .  8-| 

Ganges 9-| 

Burrampooter 9-| 

Nou  Kian,  or  Ava  River  .  .  9-| 

Jennisea 1O 

1  Oby 10! 

Amoor 11 

Lena 11-J 

Hoanho  (of  China)  ....    13A 
Kian  Keu  (of  ditto)  .  .  ,    15| 


132     Springs,  Rivers,  and  the  Sea. 
African  River. 


Nile 


American  Rivers. 
Mississippi  ........     8 

Amazons  .........  15| 

When  we  reflect  on  the  immense  length 
of  these  rivers,  and  their  origin,  we  are 
naturally  directed  to  the  contemplation  of 
the  round  which  water  travels  ;  and  by 
which,  without  suffering  adulteration  or 
waste,  it  is  continually  offering  itself  to 
the  wants  of  the  habitable  globe.  From 
the  sea  are  exhaled  those  vapours  which 
form  the  clouds  ;  these  clouds  descend  in 
refreshing  showers  of  rain,  which  sinking 
deep  into  the  earth,  form  springs,  and 
springs  uniting  form  rivers,  which  rivers 
in  return  feed  the  ocean.  So  there  is  an 
incessant  circulation  of  the  same  fluid;  and 
not  one  drop  probably  more  or  less  now 
than  there  was  at  the  creation.  In  fact, 
"  look  nature  through,  'tis  revolution  all'* 
wherever  we  turn  our  eyes,  all  seems 
continually  in  a  state  of  change  or  circu- 
lation. a  The  sun,"  saith  Solomon,  "  ari- 
seth,  and  the  sun  goeth  down,  and  pants 


Springs,  River  s^  and  the  Sea. 

for  the  place  from  whence  he  arose  ;  all 
rivers  run  into  the  sea,  yet  the  sea  is  not 
full ;  unto  the  place  from  whence  the  ri- 
vers came,  thither  they  return  again." 

The  Sea  is  a  vast  collection  of  waters  in 
the  deep  and  unfathomable  valleys  of  the 
earth.  This  great  abyss  occupies  nearly 
three  quarters  of  the  whole  surface  of  our 
globe  ;  which  has  been  thought  by  some 
too  great  a  proportion  ;  but  it  is  probably 
no  more  than  sufficient  to  fertilize  the 
land. 

The  saltness  of  the  sea  is  a  property  in 
that  element,  which  appears  to  have  exci- 
ted the  curiosity  of  naturalists  in  all  ages. 
This  property  is  very  rationally  judged 
to  arise  from  great  multitudes  both  of 
mines  and  mountains  of  salt,  dispersed 
here  and  there  in  the  depths  of  the  sea  ; 
the  salt  being  continually  diluted  and  dis- 
solved by  the  waters,  the  sea  becomes  im- 
pregnated with  its  particles  throughout  ; 
and  for  this  reason  the  saltness  of  the  sea 
can  never  be  diminished. 

The  saltness  of  the  sea  preserves  its 
waters  pure  and  sweet,  which  otherwise 
would  corrupt  and  stink  like  a  filthy  lake, 
and  consequently  none  of  the  myriads  of 


1 34     Springs,  River  s^  and  the  Sea. 

creatures  which  now  live  therein,  could 
then  have  being  ;  from  hence  also  the  sea 
water  becomes  much  heavier  ;  and  there- 
fore ships  of  greater  size  and  quantity 
may  be  used  thereon.  Salt  water  also 
doth  not  freeze  so  soon  as  fresh  water, 
whence  the  seas  are  more  free  for  navi- 
gation. 

The  most  re  mark  able  thing  in  the  sea, 
is  that  motion  of  the  water  called  tides.  It 
is  a  rising  and  falling  of  the  water  of  the 
sea.  The  cause  of  this  is  the  attraction  of 
the  moon,  whereby  the  part  of  the  water 
in  the  great  ocean  which  is  nearest  the 
moon  being  most  strongly  attracted,  is 
raised  higher  than  the  rest ;  and  the  part 
opposite  to  it,  on  the  contrary  side,  being 
least  attracted,  is  also  higher  than  the  rest. 
And  these  two  opposite  rises  of  the  sur- 
face of  the  water  in  the  great  ocean,  fol- 
lowing the  motion  of  the  moon  from  east 
to  west,  and  striking  against  the  large 
coasts  of  the  continents  that  lie  in  their 
way,  from  thence  rebound  back  again, 
and  so  make  floods  and  ebbs  in  narrow 
seas,  and  rivers  remote  from  the  great 
ocean. 

As  the  earth,  by  its  daily  rotation  round 
its  axis,  goes  from  the  moon  to  the  moon 


Springs,  Rivers,  and  the  Sea.     135 

again  (or  the  moon  appears  to  move  round 
the  earth  from  a  given  meridian  to  the 
same  again)  in  about  24  hours,  hence  in 
that  period  there  are  two  tides  of  flood 
and  two  of  ebb,  and  this  alternate  ebbing 
and  flowing  continues  without  intermis- 
sion. For  instance,  if  the  tide  be  now  at 
high -water-mark,  in  any  port,  or  harbour, 
ivhich  lies  open  to  the  ocean,  it  will  pres- 
ently subside,  and  flow  regularly  back,  for 
about  six  hours,  when  it  will  be  found  at 
low-water-mark.  After  this,  it  will  again 
gradually  advance  for  six  hours,  and  then 
return  back,  in  the  same  time,  to  its  for- 
mer situation;  rising  and  falling  alternate- 
ly, twice  a  day,  or  in  the  space  of  about 
twenty- four  hours. 

The  interval  between  its  flux  and  reflux 
is,  however,  not  precisely  six  hours,  but 
about  eleven  minutes  more ;  so  that  the 
time  of  high  water  does  not  always  happen 
at  the  same  hour,  but  is  about  three  quar- 
ters of  an  hour  later  every  day,  for  thirty 
days ;  when  it  again  recurs  as  before.  For 
example,  if  it  be  high  water,  at  any  place, 
to  day  at  noon,  it  will  be  low  water  at  ele- 
ven minutes  after  six  in  the  evening  ;  and 
consequently,  after  two  changes  more,  the 


136     Springs,  Rivers,  and  the  Sea. 

time  of  high  water  the  next  day  will  be 
about  three  quarters  of  an  hour  after  noon; 
the  day  following  it  will  be  at  about  half 
an  hour  after  one  ;  the  day  after  that  at  a 
quarter  past  two;  and  so  on  for  thirty  days 
when  it  will  again  be  found  to  be  high  wa- 
ter at  noon,  the  same  as  on  the  day  the 
observation  was  first  made.  And  this  ex- 
actly answers  to  the  motion  of  the  moon ; 
she  rises  every  day  about  three  quarters 
of  an  hour  later  than  upon  the  preceding 
one;  and,  by  moving  in  this  manner  round 
the  earth,  completes  her  revolution  in  a- 
bout  thirty  days,  and  then  begins  to  rise 
again  at  the  same  time  as  before. 

To  make  the  matter  still  plainer  ;  sup- 
pose, at  a  certain  place,  it  is  high  water  at 
three  o'clock  in  the  afternoon,  upon  the 
day  of  the  new  moon  ;  the  following  day 
it  will  be  high  water  at  about  three  quar- 
ters of  an  hour  after  three  ;  the  day  after 
that  at  about  half  an  hour  past  four ;  and 
so  on,  till  the  next  new  moon  ;  when  it 
will  again  be  high  water  about  three  o'- 
clock, the  same  as  before.  And  by  obser- 
ving the  tides  continually  at  the  same 
place,  they  will  always  be  found  to  follow 
the  same  rule  ;  the  time  of  high  water, 


Spri ngs,  Rivers,  and  the  Sea.     137 

Upon  the  day  of  every  new  moon,  being 
nearly  at  the  same  hour  ;  and  three  quar- 
ters of  an  hour  later  every  succeeding  day* 

The  attraction  of  the  sun  also  produ- 
ces a  similar  rising  and  falling  of  the  wa- 
ter of  the  ocean,  but  on  account  of  its  dis- 
tance, not  near  so  considerable  as  that 
which  is  produced  by  the  moon*  It  will 
be  readily  understood  that  according  to 
the  different  situations  of  the  sun  and 
the  moon,  the  tides  which  are  raised  by 
their  respective  attraction,  will  either  con- 
spire with,  or  counteract  each  other  in  a 
greater  or  lesser  degree.  When  they  con- 
spire together  the  tides  rise  higher,  and 
their  mutual  action  produces  what  are  cal- 
led spring1  tides*  On  the  contrary,  when 
they  counteract  each  other  they  produce 
ntap  tides.  \ 

From  a  slight  consideration  of  what 
has  been  said,  we  might  be  led  to  imagine 
that  the  time  of  high  water  at  any  place, 
would  be  when  the  moon  is  over  the  me* 
ridian  of  that  place.  But  this  is  by  no 
means  the  case  ;  it  being  usually  about 
three  hours  afterwards  :  the  reason  of 
which  may  be  shown  as  follows.  The 
moon3  when  she  15  on  the  meridian,  or 
M 


Springs^  Rivers*)  and  the  Sect. 

nearest  to  the  zenith  of  any  place,  tends 
to  raise  the  waters  at  that  place  ;  but  this 
force  must  evidently  be  exerted  for  a  con- 
siderable time,  before  the  greatest  eleva- 
tion will  take  place  ;  for  if  the  moon's  at- 
traction were  to  cease  altogether,  when 
she  has  passed  the  meridian,  yet  the  mo- 
tion already  communicated  to  the  waters 
would  make  them  continue  to  ascend  for 
some  time  afterwards,*  and  therefore,  they 
must  be  much  more  disposed  to  ascend 
when  the  attractive  force  is  only  in  a  small 
measure  diminished. 

The  waves  of  the  sea,  which  continue 
after  a  storm  has  ceased,  and  almost  eve- 
ry other  motion  of  a  fluid,  will  illustrate 
this  idea  ;  all  such  effects  being  easily  ex- 
plained, from  the  consideration  that  a 
small  impulse,  given  to  a  body  in  motion,, 
•will  make  it  move  farther  than  it  would 
otherwise  have  done.  It  is  also,  upon  the 
same  principle,  that  the  heat  is  not  the 
greatest  upon  the  longest  day,  but  some 
time  afterwards  ;  and  that  it  is  not  so  hot 
at  twelve  o'clock,  as  at  two  or  three  in  the 
afternoon  ;  because  there  is  a  farther  in- 
crease made  to  the  heat  already  imparted. 
Instead  of  its  being  high  water  then,  when 


Springs,  Rivers^  and  the  Sea.     139 

the  moon  is  upon  the  meridian  of  any 
place,  it  will  always  be  found  to  happen, 
as  far  as  circumstances  will  allow,  about 
three  hours  afterwards  ;  and  the  intervals 
between  the  flux  and  reflux,  must  be  reck- 
oned from  that  time  in  the  same  manner 
as  before. 

The  sun  being  nearer  the  earth  in  win- 
ter than  in  summer,  is  nearer  to  it  in  Feb- 
ruary and  October  than  in  March  and 
September ;  and  therefore  the  greatest 
tides  happen  not  till  some  time  after  the 
autumnal  equinox,  and  return  a  little  be- 
fore the  vernal. 

The  tide  propagated  by  the  moon  in  the 
German  ocean,  when  she  is  three  hours 
past  the  meridian,  takes  twelve  hours  to 
come  from  thence  to  London  Bridge  ; 
where  it  arrives  by  the  time  that  a  new 
tide  is  raised  in  the  ocean. 

These  are  the  principal  phenomena  of 
the  tides  ;  and  where  no  local  circumstan- 
ces interfere,  the  theory  and  facts  will  he 
found  to  agree.  <But  it  must  be  observed 
that  what  has  been  here  said,  relates  only 
to  such  places  as  lie  open  to  large  oceans. 
In  seas  and  channels,  which  are  more  con- 
fined, a  number  of  causes  concur,  which 


140    Springs j  Rivers,  and  the  Sea. 

occasion  considerable  deviations  fiom  the 
general  rule.  Thus,  it  is  high  water  at 
Plymouth  about  the  sixth  hour ;  at  the 
Isle  of  Wight  about  the  ninth  hour  ;  and 
at  London  bridge  about  the  fifteenth  hour 
after  the  moon  has  passed  the  meridian. 
And  at  Batsha,  in  the  kingdom  of  Ton- 
quin,the  sea  ebbs  and  flows  but  once  a  day 
the  time  of  high  water  being  at  the  setting 
of  the  moon,  and  the  time  of  low  water  at 
her  rising.  There  are  also,  great  varia- 
tions in  the  height  of  the  tides,  according 
to  the  situation  of  coasts,  or  the  nature  of 
the.  straits  which  they  have  to  pass  through. 
Thus,  the  Mediterranean  and  Baltic  seas 
have  very  small  elevations  ;  while,  at  the 
port  of  Bristol,  the  height  is  sometimes 
near  thirty  feet ;  and  at  St.  Malo's  it  is 
$aid  to  be  still  greater. 


Fvssik*  1.41 


CHAP.  IX. 

Of  Earths,  Stones,  Metals,  Miner- 
als, and  other  Fossils. 

HAVING  taken  a  view  of  the  air 
which  surrounds,  and  the  water  which 
diversifies  the  face  of  our  globe,  we  will 
now  take  a  survey  of  the  solid  substance, 
or  body  of  our  earth. 

Those  who  observe  the  disposition  of 
the  earth,  as  it  appears  in  the  quarrying 
or  digging  of  mines,  find  it  generally  ly- 
ing in  horizontal  layers,  or  strata  of  dif- 
ferent kinds,  like  the  settlings  of  waters* 
The  first  layer  that  presents  itself,  is  most 
commonly  the  bed  of  vegetable  earth  or 
mould.  With  this  earth  the  surface  of 
our  globe  is  generally  covered*  It  is 
this  mould  which  gives  rooting  and  nour- 
ishment to  plants,  so  that  they  may  stand 
and  grow  in  it,  and  it  is  as  it  were  the 
store-house  from  whence  all  the  living 
M2 


142  Fossils. 

creatures  of  our  world  have  originally 
their  provisions  ;  for  from  thence  all  the 
plants  have  their  sustenance,  and  some 
few  animals,  and  from  these  all  other  an- 
imals. 

As  this  affords  to  animals  and  vegeta- 
bles their  support,  so  the  spoils  of  these, 
when  dead  or  decayed,  return  to  the  dust 
of  the  ground,  from  whence  they  were 
formed,  and  thus  keep  up  an  unceasing 
circulation. 

The  most  common  disposition  of  the 
layers  is,  that  under  the  first  earth  is 
found  gravel  or  sand  ;  clay  or  marl ;  then 
chalk,  or  coal,  marbles,  ores,  &c.  This 
disposition,  however,  is  far  from  being 
uniformly  continued  all  over  the  globe  ; 
in  different  soils  the  order  of  these  layers 
vary. 

It  is  wonderful  the  variety  of  produc- 
tions which  are  found  in  the  different 
parts  of  our  globe.  In  the  crumbling 
chalk,  the  solid  marble,  the  dusty  gravel, 
and  even  the  depths  of  the  most  inland 
valleys,  and  on  the  summits  of  the  high- 
est mountains,  we  behold  the  spoils  of  the 
ocean,  exhibited  under  the  several  ap- 
pearances of  petrified  fish,  beds  of  shells^ 


Fossils.  143 

and  sea  plants.  The  Alps,  the  Apen- 
nines, the  Pyrenees,  Libanus,  Atlas,  and 
Ararat,  every  mountain  of  every  coun- 
try under  heaven,  where  search  has  been 
made,  all  conspire  in  one  uniform  and 
universal  proof,  that  the  sea  has  covered 
their  highest  summits.  If  we  examine 
the  earth,  we  shall  find  the  mouse  deer, 
natives  of  America,  buried  in  Ireland  ; 
elephants,  natives  of  Asia  and  Africa, 
buried  in  the  midst  of  England  ;  croco- 
diles, natives  of  the  Nile,  in  the  heart  of 
Germany  ;  shell-fish,  never  known  but 
in  the  American  seas,  together  with  skel- 
etons of  whales,  in  the  most  inland  re- 
gions of  England  ;  trees  of  vast  dimen- 
sions with  their  roots  and  tops  at  the  bot- 
tom of  mines  and  marls,  found  in  regions 
where  such  trees  were  never  known  to 
grow,  nay,  where  it  is  demonstrably  im- 
possible they  could  grow.  Such  are  the 
awful  memorials  of  the  great  convulsions 
and  revolutions  which  have  taken  place 
in  the  natural  world  ;  of  countries  laid 
under  the  rolling  waves  of  the  ocean  ; 
and  of  lands  rising  from  the  midst  of  the 
waters,  and  becoming  the  habitations  of 
beasts  and  of  men  ;  so  transient  fiiicl  un 
certain  are  all  earthly  things. 


144  Fossils. 

The  various  bodies  which  are  found 
by  digging  in  the  earth  are  called  fossil 
substances  \  under  which  are  comprehen- 
ded metals,  minerals,  stones  of  divers 
kinds,  and  sundry  bodies  that  have  the 
texture  between  earth  and  stone. 

These  bodies  are  divided  into  four 
different  classes  by  mineralogists,  viz. 
I.  Earth  and  Stones  in  general ;  II.  Salts ; 
III.  Inflammables  ;  and  IV.  Metals. 

I.  Earth  and  Stones  in  general  are  1st, 
mould  the  support  of  vegetables;  2nd, 
clays,  which  mixed  with  water  harden  in 
the  fire,  into  bricks,  delf,  china,  &c.  3d, 
calcareous  substances,  as  chalks,  marls, 
limestones,  marbles,  convertible  by  heat 
into  quicklime,  and  gypsum  into  alabas- 
ter ;  4th,  talcs,  which  are  found  in  flat, 
smooth  laminae  ;  5th,  slates  also  split  into 
laminae ;  these  with  a  variety  of  stones 
from  freestone,  or  sand,  to  granite,  por- 
phyry, flint,  and  substances  still  harder, 
such  as  precious  stones,  are  known  by  va- 
rious properties,  and  are  accordingly  ap- 
plied to  different  purposes  ;  some,  in  ad- 
dition to  being  serviceable  in  building,  are 
used  as  whetstones  ;  some  strike  fire  with 
steel ;  others  are  polished  to  glitter  in  the 


Fossils. 

dress  ofthe  fair,  or  decorate  the  furniture 
of  the  opulent ;  and  others,  melted  by  fire, 
form  the  transparent  glass. 

Although  there  seems  to  be  an  almost 
infinite  variety  of  earthly  substances  scat- 
tered on  the  surface  of  this  globe  yet  when 
we  examine  them  chemically,  \ve  find 
that  all  the  earth  and  stones  which  we 
tread  under  our  feet,  and  which  compose 
the  largest  rocks  as  well  as  the  numerous 
different  specimens  which  adorn  the  cabi- 
nets of  the  curious,  are  composed  of  a 
very  few  simple  or  elementary  earths,  the 
principal  of  which  are  the  calcareous,  si- 
liceous, argillaceous,  magnesia,  terra  pon- 
derosa,  and  a  few  others  which  have  been 
discovered  lately,  but  have  not  been  much 
examined. 

Calcareous  earth  is  found  in  the  shells 
of  fishes,  the  bones  of  animals,  chalk, 
limestone,  marble,  and  gypsum  :  but  all 
calcareous  earth  is  supposed  to  be  of 
animal  origin  ;  and  beds  of  chalk,  lime- 
stone, or  marble,  are  thought  to  have 
been  beds  of  shells  formed  in  the  sea,  in 
some  pristine  state  of  the  earth. 

Silex,  or  siliceous  earth  is  the  princi- 
pal constituent  part  of  a  great  number  of 


146  Fossils. 

the  compound  earths  and  stones,  forming 
the  immense  mass  of  the  solid  nucleus 
of  the  globe.  It  is  the  base  of  almost 
all  the  scintillating  stones,  such  as  flint, 
rock,  crystal,  quartz,  agate,  calcedon, 
jasper,  &JV.  The  sand  of  rivers  and  of 
the  sea-shore,  chiefly  consists  of  it. 

Argillaceous  earth  is  found  in  clay^ 
schistus,  or  slate,  and  in  mica.  This 
species  of  earth  is  ductile  with  water,  it 
then  hardens  and  contracts  by  heat,  so 
as  to  be  of  the  greatest  use  in  forming 
brick,  or  stones  of  any  required  form  or 
size. 

Terra  ponder osa  is  generally  found  in 
two  states,  viz.  united  to  vitriolic  acid, 
when  it  is  called  calk;  or  to  fixed  air,  when 
it  is  called  terra  ponderosa  aerata.  This 
earth  is  distinguishable  by  its  great  speci- 
fic gravity,  being  four  times  as  heavy  as 
water. 

Magnesia  is  found  sometimes  pure  in 
nature,  but  it  is  generally  obtained  by  art 
from  some  of  its  combinations.  It  gives 
a  peculiar  character  to  the  substances  of 
which  it  forms  a  part.  The  stones  which 
contain  magnesia  in  considerable  quantity 
'  .have  generally  a  smooth  and  unctuous  feel? 


Fossils.  147 

a  greenish  cast,  a  fibrous  striated  tex- 
ture, and  a  silky  lustre.  Among  them  we 
may  mention  talc,  steatite,  serpentine, 
chlorite,  asbestos,  &c.  Pure  magnesia 
does  not  form  with  water  an  adhesive  duc- 
tile mass.  It  is  in  the  form  of  a  very 
white  spongy  powder  and  perfectly 
tasteless. 

Stones  are  formed  by  the  mixtures  of 
the  earths  together,  and  of  the  mixtures  of 
earths  with  alkalies,  and  sometimes  with 
acids.  Stones  bound  together  by  some 
cement,  form  rocks.  There  is  also  a  kind 
of  stones  of  a  peculiar  nature  produced  by 
the  fire  of  volcanoes. 

The  stones  in  which  the  acids  and  al- 
kalies abound  are  called  saline  stones,  and 
the  mixtures  of  the  earths  with  each  oth- 
er form  stones  properly  so  called.  Of 
stones  properly  so  called,  those  in  which 
the  siliceous  earth  abounds  and  predom- 
inates are  very  numerous  ;  the  principal 
of  which  we  shall  briefly  notice. 

Siliceous  mixtures  have  sufficient  hard- 
ness to  strike  fire  with  steel.  Of  this  de- 
scription are  the  precious  stones,  rock  crys- 
tat,  or  quartz,  felspar,  silex,  crysopryse^ 
lapis  lazuli,  jasper,  and  schorl* 


148  fossils. 

Gems,  or  precious  stones,  are  of  various 
kinds.  They  are  distinguished  by  their 
hardness,  weight,  colour,  and  splendour^ 
as  well  as  by  their  property  of  producing 
single  or  double  refractions.  As  their 
colour  is,  of  all  their  characters,  the  most 
apparent,  it  is  according  to  this  that  we 
shall  divide  them. 

Red  gems  are  the  ruby,  the  vermillion9 
garnet  and  girasol.  The  ruby  is  a  trans- 
parent stone,  the  colour  of  which  is  more 
or  less  red.  It  is  distinguished  into  four 
kinds,  viz.  the  oriental  ruby,  the  spinel 
ruby,  the  balass  ruby,  and  the  Brazilian 
ruby. 

fellow  gems  are  the  topaz,  hyacinth  and 
jargon  of  Ceylon.  Of  the  topaz,  there  are 
three  kinds,  the  oriental  topaz,  the  Bra^ 
zilian  topaz,  and  the  Saxon  topaz. 

Blue  gems  are  the  sapphire,a.ud  the  aiguc 
marine.  There  are  two  kinds  of  the  sap- 
phire, viz.  the  oriental  sapphire,  and  the 
Brazilian.  There  are  also  two  kinds  of 
the  aigue  marine,  the  oriental  and  the 
occidental. 

Green  gems  are  the  emerald  of  Peru  and 
the  chrysolite,  of  which  there  are  two 
kinds,  viz.  the  Brazilian,  accl  that  of  the 
jewellers. 


fiossik.  149 

The  diamond  ought  certainly  to  be  pla- 
ced among  the  precious  stones,  but  it  is 
different  from  all  those  above  described. 
Its  combustibility  is  a  property  entirely 
peculiar  to  itself;  the  diamond  indeed 
burns  hi  the  same  manner  as  phosphorus, 
disappears  without  leaving  any  vestiges  of 
it  behind.  The  diamond  is  supposed  to 
be  pure  carbon,  and  the  radical  of  the 
carbonic  acid. 

There  are  several  varieties  of  the  dia- 
mond, which  differ  from  each  other  only 
in  colour  ;  some  are^f  a  rose  colour,  and 
others  red,  orange,  yellow,  green,  blue  and 
dark  coloured. 

Rock-crystal  and  quartz  seem  to  be  the 
same  stone*  The  name  of  rock-crystal 
is  given  to  that  which  is  crystallized,  and 
of  quartz  to  that  which  is  in  a  rude  mass. 
The  form  of  these  crystals  is  a  hexadral 
prism,  terminated  at  one  of  its  extremities 
and  sometimes  at  both,  by  a  summit  com- 
posed of  six  triangular  faces.  In  hardness 
they  are  inferior  to  all  the  other  gems. 
Rock-crystal  consists  almost  entirely  of 
pure  silex.  Quartz  enters  into  the  com- 
position of  granite. 

Freestone  is  of  the  same  i^ature  as 
N 


130  Fossils. 

quartz.  It  is  granulated,  being  composed 
of  sir.  all  grains  of  quartz,  cemented  toge- 
ther, but  which  have  very  little  adhesion. 

Fehpar  is  inferior  in  hardness  to 
quartz.  It  fuses  by  the  action  of  heat, 
and  forms  white  enamel.  It  is  one  of 
the  constituent  parts  of  porcelain. 

We  may  mention,  under  this  class,  ad- 
amantine spar,  which  approaches  near  to 
the  preceding  in  its  appearance  and  frac- 
ture, but  which  differs  from  them  con- 
siderably,  by  its  great  hardness,  its  form, 
and  gravity.  It  is  so  exceedingly  hard, 
thai  it  may  be  employed  to  cut  the  dia- 
mond. 

Flint  is  a  stone  *  which  is  so  hard  as  to 
strike  fire  with  steel,  Among  the  dif- 
ferent \  rid  of  flints,  some  change  their 
colour  according  to  the  directions  of  the 
rays  of  light,  and  others  do  not.  Of  the 
former  there  are  three,  the  opal,  the  cat's- 
eye  and  iheji.s/i-et/e. 

The  kinds  of  flints  which  do  not  change 
their  colour  according  to  the  direction  of 
the  rays  of  light,  exhibit  tints  of  more  or 
less  brightness,  and  are  susceptible  of  a 
fine  polish.  We  are  acquainted  with 
eight  kinds  of  them,  viz.  common  Jtint^ 


Fossils.  1 5  ': 

petro  si  lex,  agate,  calcedony,  cornelian, 
3arcknyx,\\\zjade,  and  iheprasium. 

Common  flint  posesses  very  little 
transparency.  All  the  different  kinds  of 
it  have  a  dark  dull  colour,  and  are  con- 
cave, or  convex,  on  the  fracture.  They 
do  not  fuse  in  the  fire,  but  are  calcined 
and  become  white. 

The  distinguishing  character  of  petro 
silex  is  its  semi-transparency,  similar  to 
that  of  wax.  It  becomes  white  in  the 
fire,  like  the  common  flint,  but  it  is  more 
fusible,  as  it  runs  without  any  addition. 

Agate  has  a  smooth  shining  fracture, 
and  will  take  a  very  high  polish ;  it  is 
much  variegated.  When  exposed  to 
heat,  it  loses  its  colour,  and  becomes  o~ 
paque,  but  without  fusing. 

The  calcedony  has  a  milky  semi-trans- 
parency. Every  kind  of  it  takes  a  fine 
polish.  These  stones  are  white,  inter- 
mixed sometimes  with  tints  of  red,  yel- 
low, and  blue. 

The  cornelians  are  all  either  entirely^ 
or  in  part,  of  a  beautiful  red  colour,  but 
they  lose  their  colour  in  the  fire,  and  be- 
come opaque.  They  are  all  susceptible 
of  a  fine  polish. 


152  Fossils. 

Lapis  lazuli  is  of  a  beautiful  sky- 
blue  colour,  sometimes  mixed  with  white, 
and  is  entirely  opaque.  It  is  sometimes 
mixed  with  pyrites,  from  which  it  has 
been  supposed  that  it  contained  gold.  If 
exposed  to  a  strong  heat,  it  fuses,  and 
forms  a  sort  of  whitish  glass  ;  when  cal- 
cined, it  dissolves  in  acids  into  a  kind  of 
jelly.  Lapis  lazuli,  when  pulverized, 
forms  that  valuable  colour  known  under 
the  name  of  ultramarine. 

Jasper  is  a  stone  which  exhibits  every 
variety  of  colour.  It  is  exceedingly  hard, 
and  receives  a  very  beautiful  and  dura- 
ble polish.  When  exposed  to  the  action 
of  heat,  it  does  not  fuse. 

Schorl  is  a  hard  stone,  fusible  in  a 
moderate  fire,  without  any  addition.  Its 
crystals  exhibit  a  great  variety,  in  regard 
to  form,  appearance,  texture,  structure, 
&c.  Schorl,  in  general,  is  opaque  ;  some 
kinds,  however,  are  transparent,  such  as 
Brazilian  emerald,  the  peridot^  the  tour- 
malm,  &?c. 

The  colour  of  schorl  is  various  ;  some, 
kinds  are  black,  others  violet,  and  some 
green.  Schorl  enters  into  the  composi- 
tion of  porphyry,  serpentine,  the  ophite, 
granitelL  and  granite. 


Fossils.  153 

The  primitive  earths  form  stones,  as 
we  have  mentioned,  and  stones  united  by 
cement  form  those  masses  called  rocks. 
We  shall  notice  the  six  mixtures  which 
are  most  commonly  found  in  those  mas- 
ses, viz.  porphyry,  serpentine,  ophites 
granitell,  granite,  andjtint. 

Porphyry  is  composed  of  felspar  in 
small  fragments,  of  schorl,  and  a  kind  ot 
cement,  which  unites  ail  the  parts,  and 
which,  in  some  measure,  forms  the  base. 
Porphyry  is  exceedingly  hard,  and  diffi- 
cult to  be  cut  j  it  will,  however,  take  a  fine 
polish.  Some  kinds  of  it  are  red,  and 
others  green. 

Serpentine  is  composed  of  the  same 
substance  as  porphyry.  The  only  differ- 
ence is,  that  the  felspar  is  in  larger  frag- 
ments. The  colour  of  serpentine  is  vari- 
ous ;  some  kinds  are  green,  others  violet, 
some  yellow,  and  some  black. 

The  ophite  is  composed  of  only  two 
substances,  viz.  black  schorl,  known  un- 
der the  name  of  ancient  black  basaltes, 
interspersed  with  greenish  felspar,  which 
forms  in  it  long  spots.  This  stone  has 
considerable  hardness. 
N2 


154  Fossils. 

Granitell  is  also  composed  of  two  sub- 
stances ;  black  schorl,  and  white  felsper, 
mixed  with  some  of  the  green  felspar. — 
The  only  difference  then  between  the 
granitelles  and  the  ophite  is,  that  the 
schorl  which  enters  into  the  composition 
of  the  former  is  not  of  the  same  kind  as 
that  in  the  latter. 

Granite  is  composed  of  felspar,  schorl, 
and  quartz.  The  colour  of  granite  is 
various  ;  it  is  hard,  difficult  to  be  work- 
ed, and  receives  a  fine  polish- 

Flint  is  a  hard  opaque  stone,  suscepti- 
ble of  a  very  beautiful  polish.  It  appears 
to  be  composed  of  concentric  strata,  and 
has  considerable  brilliancy  on  its  frac- 
ture. Flints  are  never  found  in  continued 
quarries,  like  the  other  stones  ;  they  are 
found  detached,  and  dispersed  through- 
out the  fields.  When  joined  by  any 
kind  of  cement  they  form  pudding-stones. 
They  become  decomposed  in  the  air,  for 
they  are  found  for  the  most  part  covered 
•with  a  crust,  of  a  softer  nature  than  the 
interior  part.  Their  colour  is  exceeding- 
ly various ;  some  of  them  are  spotted  and 
yariegated  with  veins,  others  exhibits 
the  resemblance  of  plumes,  and  even  of 
plants. 


155 

Vakonic  Productions  are  chiefly  pum- 
ice-stones, lava  and  basaltes. 

Pumice-stone  is  real  glass,  in  the  form 
of  small  greyish,  white,  and  exceeding- 
ly brilliant  filaments.  These  filaments 
always  leave  vacuities  of  greater  or  less 
size  between  them,  which  occasions  great 
variations  in  its  specific  gravity.  In 
general  it  is  lighter  than  water. 

Lava  is  that  burning  matter  which  runs 
down,  in  such  prodigious  quantities,  from 
volcanoes,  when  in  a  state  of  eruption., 
and  often  extends  to  a  great  distance. 
This  matter  is  a  semi-vitrified  substance, 
which  appears  blackish,  on  account  of 
its  density. 

Basaltes  is  blackish  and  opaque.  By 
the  action  of  heat  it  may  be  converted 
into  glass,  of  a  very  beautiful  black  co- 
lour. It  often  crystallizes  in  prisms, 
of  three,  four,  five,  six,  or  seven  planes- 
Of  some  kinds,  such  as  that  known  un- 
der the  name  of  touchstone,  the  grain  is 
exceedingly  fine. 

II.  Of  Salts. — The  alkalies,  the  acids, 
and  the  combinations  in  which  they  enter 
insufficient  quantities,  are  called  salts , 


156  Fossils. 

or  saline  substances;  for  a  saline  sub- 
stance, in  its  extended  chemical  sense, 
means  a  substance  that  has  some  taste, 
and  is  soluble  in  water.  These  sub- 
stances, however,  do  not  strictly  and  ex- 
clusively belong  to  the  fossil  department, 
but  are  obtained  also  from  animal  and 
vegetable  substances.  They  are  the  most 
active  agents  in  creation.  They  give 
bodies  their  consistency  ;  preserve  them 
from  corruption,  and  render  them  sa- 
voury. 

Alkalies  are  distinguishable  by  their 
acrid,  burning,  and  urinous  taste,  their 
causticity,  their  singular  action  on  the 
skin  and  all  animal  substances,  the  quali- 
ty of  changing  the  blue  colour  of  violets 
to  a  green,  and  even  a  greenish  yellow, 
and  deliquescency.  We  are  acquainted 
with  three  species, — potash,  soda,  and 
ammonia.  The  first  and  second  have 
been  called  fixed  alkalies,  because  they 
melt  and  grow  red  in  the  fire  before 
they  become  volatile  ;  the  third  has  been 
named  volatile  alkali,  from  possessing  the 
opposite  property. 

Potash  is  known  by  the  following  char- 
acters :—It  is  dry,  solid,  white,  and  very 


Fossils.  157 

deliquescent,  absorbs  water  with  heat 
and  a  peculiar  faint  smell,  combines  with 
siliceous  earth  by  fusion,  and  forms  glass. 
It  is  frequently  found  native  with  lime, 
and  combined  with  different  acids  ;  but 
is  chiefly  obtained  from  vegetables,  in 
the  ashes  of  which  it  remains  after  com- 
bustion. 

Soda  or  the  mineral  alkali,  is  procured 
from  the  ashes  of  sea-weed,  and  consti- 
tutes the  basis  of  sea-salt.  It  strikingly 
resembles  potash  in  form,  causticity,  fusi- 
bility, deliquescency,  combination  with 
earthy  substances,  by  means  of  fusion, 
action  on  animal  substances,  Sec.  so  that 
it  was  long  confounded  with  it,  and  might 
have  continued  to  be  so,  if  it  did  not  form 
very  different  salts  with  acids,  and  yields 
these  acids  to  potash. 

Ammonia,  or  volatile  alkali,  differs 
greatly  from  the  two  preceding  species 
in  its  form  of  gas  when  dissolved  in  cal- 
coric,  in  its  liquid  form  when  dissolved  in 
water,  in  its  pungent  and  suffocating 
smell,  its  solubility  in  air,  &c.  Am- 
monia is  procured  by  burning  animal 
substances ;  in  Egypt,  (from  whence,  as 
contained  in  sal  ammoniac  we  till  of  late 


158  Fossils. 

imported  it)  from  camels'  dung  ;  but 
now  from  bones  by  distillation. 

All  Acids  appear  to  be  combinations  of 
oxygen  or  vital  air,  with  elementary  sub- 
stances. Their  taste  is  sour,  as  their 
name  imports.  They  change  most  of 
the  blue  vegetable  colours  red,  and  have 
a  tendency  to  combine  with  earths,  alka- 
lies, and  metallic  substances. 

All  acids,  being  compounds  of  oxygen 
with  different  substances,  the  former  prin- 
ciple is  the  cause  of  their  resemblance  and 
common  properties  ;  the  latter,  being 
different  in  each,  may  serve  to  character- 
ize each  in  particular.  For  this  reason 
those  matters  which  are  variable  in  acids 
are  termed  their  radicals,  or  acidifiable 
principles.  Thus  all  acids  are  combina- 
tions of  radicals,  or  acidifiable  substan- 
ces, different  in  each  species,  with  oxy- 
gen, which  is  the  same  in  all :  whence  it 
follows,  that  their  common  properties, 
their  characters  as  acids,  depend  on  oxy- 
gen, which  is  the  acidifying  principle  ; 
their  particular  properties,  their  specific 
characters  arise  from  their  radicals.  The 
word  acid,  indicating  the  general  and 
identical  nature  of  these  substances,  forms 
their  generical  name,  while  the  particular 


Fdssifo*  159 

name  of  the  radical  contained  in  each  may 
with  propriety  designate  each  particular 
acid. — Thus  sulphur  is  the  radical  of  the 
acid  we  name  sulphuric,  phosphorus  that 
of  the  phosphoric,  carbon  that  of  the 
carbonic,  and  so  on. 

Acidifrable  radicals  may  contain  differ- 
ent quantities  of  oxygen,  .and  under  this 
point  of  view  they  possess  two  states  of 
acidity.  The  first  is  that,  in  which  they 
contain  the  least  possible  quantity  of  oxy- 
gen to  render  them  acid.  In  this  their 
acidity  is  commonly  weak,  and  they  adhere 
but  feebly  to  the  bases  with  which  they 
are  capable  of  forming  salts.  The  mod- 
ern methodical  nomenclature  designates 
this  state  of  combination  and  acidity ^  by 
giving  the  names  of  these  weak  acids  the 
termination  ous.  Thus  wre  say  the  sulphu- 
rous, nitrous,  phosphorous,  or  acetous^ 
acid.  The  second  state  of  acids  is  that,, 
in  which  they  contain  more  oxygen,  and 
in  general  are  completely  saturated  with 
it.  In  this  they  have  all  the  strength  and 
attraction  they  are  capable  of  possessing 
as  acids,  and  the  modern  nomenclature 
expresses  it  by  the  termination  zc.  Thus 
we  say  the  sulphuric,  nitric,  phosphoric,, 


16O  Fossils. 

or  acetic,  acid.  With  regard  to  the  pro* 
portion  of  oxygen  united  to  acidifiable  ra- 
dicals, still  greater  latitude  may  be  given 
to  the  considerations  presented  above. 
Each  radical  may  be  contemplated  in  four 
states  :  1st,  containing  very  little  oxygen 
not  sufficient  to  impart  to  it  the  nature  of 
an  acid,  and  in  this  it  is  nothing  more  than 
an  oxyd  ;  such  is  sulphur  coloured  red  or 
brown,  by  exposure  to  the  air,  and  a  de- 
gree of  heat  inadequate  to  produce  infla- 
mation  ;  when  it  is  oxyd  of  sulphur  ;  2dly 
containing  more  oxygen  than  in  the  pre- 
ceding case,  and  enough  to  become  an  a- 
cid,  though  weak  ;  as  in  the  sulphurous 
acid  ;  3dly,  possessing  still  more  oxygen 
than  in  the  second  instance,  and  having 
acquired  powerful  acid  properties  ;  such 
as  the  sulphuric  acid  ;  ithly,  conjoined 
with  a  larger  dose  of  oxygen  than  is  neces- 
sary to  constitute  a  powerful  acid,  an  acid 
in  ic ;  when  it  is  termed  an  oxygenated 
acid,  or  even  super-oxygenated. 

The  acids  are  generally  divided  into 
mineral,  vegetable,  and  animal,  acids,  ac- 
cording to  the  nature  of  their  radicals. 
Though  the  first  class  only  with  propriety 
claims  notice  in  this  place,  yet  for  the  in- 


Fossils.  161 

formation  of  the  reader  we  will  enumerate 
those  belonging  to  each  of  the  above 
classes. 

The  miner  a  I  acids  at  present  known  are 
the  sulphuric  (formerly  called  the  vitriolic 
acid);  the  nitric  acid,  called  also  aquafor- 
tis; the  muriatic  or  marine  acid,  called  by 
artizans  the  spirit  of  salt ;  the  carbonic 
acid,  formerly  called  the  acid  of  charcoal, 
aerial  acid,  or  fixed  air,  &c.  the  phospho- 
ric acid,  which  is  likewise  an  animal  acid, 
it  being  found  amongst  animal  matters  as 
well  as  among  minerals  ;  the  acid  of  bo- 
rax ;  the  flouric  acid,  formerly  called  the 
acid  of  spar  /the  arsenic  acid  ;  the  moiyb- 
die  acid ;  the  tungstenic  acid  ;  and  the 
chromic  acid.  The  last  four  are  also 
called  metallic  acids. 

The  vegetable  acids  are  the  acetic,  or 
vinegar,  the  acid  of  tartar,  the  empyreu- 
matic  acid  of  tartar,  the  oxalic  or  acid  of 
sorrel,  the  acid  of  galls,  the  citric  or  lem- 
on acid,  the  malic  or  acid  of  apples,  the 
benzoic,  or  the  acid  of  benjamin,  the  em- 
pyreumatic  acid  of  sugar,  the  acid  of  cam- 
phor, and  the  suberic  or  acid  of  cork. 

The  animal  acids  are,  the  acid  of  milk, 
the  acid  of  sugar  of  mu%  the  formic  or  a- 
O 


162  Fossils* 

cid  of  ants,the  prussic  acid,  viz.  the  colou- 
ring matter  of  prussian  blue,  which  is  ob- 
tained from  dried  blood,  hoofs,  &c.the  se~ 
bacic  or  acid  of  fat,  the  bombic  or  acid  of 
silk- worms,  the  laccic  or  the  acid  of  waxy 
matter,  and  the  zoonic,  or  the  acid  extrac- 
ted from  animal  matter  by  means  of  lime. 

For  a  more  full  account  of  these  acids 
we  refer  the  reader  to  various  recent  pub- 
lications, written  professedly  on  the  sub- 
ject of  chemistry. 

Acids  and  alkalies,  shew  strong  attrac- 
tions for  each  other,  and  when  combined 
together  in  such  proportion  that  neither  of 
them  predominates,  form  neutral  salts  : 
substances  altogether  dissimilar  to  the 
elements  of  which  they  are  composed. 
The  salt  in  common  use  for  instance,  is 
formed  of  mineral  acid  and  alkali ;  either 
of  which,  singly,  would  be  hurtful  to  the 
human  body  ;  and  the  acid,  in  particular, 
would  be  extremely  pernicious. 

Each  acid  produces  with  each  of  the 
three  alkalies  a  particular  neutral  salt. 
The  number  of  the  last  may  therefore 
be  found  by  multiplying  the  number  of 
the  acids  which  we  know,  by  three^  the 
number  of  the  alkalies* 


Fossils* 


III.  Inflammables.  —  Inflammables  are 
sulphur  or  bitumens.  These  substances 
are  both  derived  from  the  spoils  of  vege- 
tables and  animals. 

Sulphur,  known  also  by  the  name  of 
brimstone,  is  a  simple  combustible  sub- 
stance, which  nature  frequently  presents 
in  a  pure  state.  It  is  found  in  the  earth 
in  a  loose  powder,  or  solid  ;  and  either 
detached  or  in  Veins.  It  is  met  with  in 
the  greatest  plenty  in  the  neighbourhood 
of  volcanoes,  and  is  deposited  as  a  crust 
on  stones  contiguous  to  them.  It  is  al- 
so met  with  in  mineral  waters,  coal-mines, 
£?c.  and  also  in  combinations  with  most 
of  the  metals. 

The  bitumens  are  naptha,  petrol,  min- 
eral tar,  asphaltum,jet,  cannel-coal,  min- 
eral tallow,  pit-coal,  amber,  &c. 

Naptha  is  a  white  or  yellowish  white 
substance,  fluid  as  water,  feels  greasy, 
has  a  penetrating  smell,  and  burns  with  a 
light  flame,leavmg  scarcely  any  residuum. 

Petrol,  or  Petroleum,  is  a  brown  semi- 
transparent  substance  ;  being  naptha, 
thickened,  and  altered  in  colour  and  other 
respects  by  the  air. 


164  Fossils. 

Mineral  Tar  is  petrol  farther  altered  by 
the  air,  having  become  of  the  colour  and 
consistency  of  pitch. 

Asphaltum,  or  mineral  pitch ^  is  produ- 
ced by  a  still  farther  exsiccation  or 
drying. 

Jet  is  a  substance  of  a  full  black,  hard- 
er, and  less  brittle  than  asphalt ;  and  ac- 
cording to  Wtdcnrnan,  is  a  species  of 
coal. 

Cannell'Coal  appears  to  be  next  to  jet, 
in  gradation,  of  the  compound  mineral 
bituminous  substances. 

Mineral  Tallow  is  rarely  met  with,  and 
imperfectly  known.  It  much  resembles 
tallow. 

Mineral  Caoutchouc  is  a  substance 
much  resembling,  in  its  elastic  properties, 
the  substance  from  which  it  takes  its 
name. 

Pit-coal,  according  to  Mons.  Gensannc 
and  others,  is  an  earth  or  stone,  chiefly  of 
the  argillaceous  genus,  penetrated  or  im- 
pregnated with  petrol  or  asphalt.  It  has 
also  been  supposed  to  hav7e  been  formed 
by  vegetables  growing  in  the  sea,  and  by 
vast  forests  which  have  been  buried  br 
subsequent  revolutions, 


Fossils*  1 6-5 

Amber  is  a  bitumen  generally  of  a  yel- 
low or  brown  colour.  It  is  found  either 
under  the  surface  of  the  ground,  among 
the  clay,  sand,  and  iron  bog  ore,  when  it 
is  called  yissz/  amber,  or  is  thrown  on  the 
shore  by  the  waters  of  the  sea,  and  is  then 
called  mineral  amber.  It  is  tasteless,  but 
when  rubbed  it  yields  a  faint  odour,  and 
manifests  electric  powers. 

IV.  Metals. — We  are  at  present  ac- 
quainted with  twenty -one  metallic  sub- 
stances, essentially  different  from  each 
other;  gold,platina,  silver,  mercury,  lead, 
copper,  iron,  tin,  zinc,  bismuth,  antimony, 
arsenic,  cobalt,  nickel,  manganese,  molyb- 
dena,  wolfram, chrome,uranium,titanium% 
and  tellurium. 

Metals  exceed  all  other  fossils  in  spe- 
cific gravity  ;*  but  there  exists,  in  this 

*The  specific  gravity  of  any  body  is  the  proportion 
which  its  weight  bears  to  the  weight  of  another 
body  of  equal  bulk.  The  established  custom  is  to 
compare  all  bodies  with  water,  the  specific  gravity 
of  which  is  reckoned  one,  or  unity;  so  that  when 
the  specific  gravity  of  anybody,  asGold,for  instance, 
5s  said  to  be  19,  Zinc  7,  we  mean  that  equal  quan- 
tities of  Water,  Gold,  and  Zinc  weigh  respectively 
1,  19,  and  7,  be  they  pounds,  ounces,  grains,  or  any 
other  weights.  O2 


166  Fossils. 

respect,  a  remarkable  difference  among 
themselves.  They  are  completely  opaque. 
They  also  possess  a  mirror-like  lustre, 
which  is  one  of  their  characteristic  marks 
and  they  present  a  convex  surface  when 
melted  in  earthen  vessels.  Besides,  they 
are  all  insoluble  in  water.  And  by  these 
external  characters,  it  is  easy  to  distin- 
guish this  class  from  all  other  fossils,  viz. 
earths,  salts,  bitumens,  and  sulphur. 

Metals  are  concealed  in  the  earth,  and 
form  ores,  which  existing  in  crevices  of 
rocks,  are  called  ^Z72,9,and  are  distinguish- 
ed into  level,  or  into  inclined,  direct  or 
oblique,  according  to  the  angle  they  make 
with  the  horizon.  The  part  of  the  rock 
resting  on  the  vein,  is  termed,  the  roof; 
and  that  on  which  the  vein  rests,  the  bed  of 
the  vein.  And  the  cavites  made  in  the 
earth,  in  order  to  extract  these  ores,  are 
called  mines. 

When  nature  has  bestowed  on  metals 
their  proper  metallic  appearance,  or  they 
are  only  alloyed  with  other  metals,  they 
are  said  to  be  native.  When  combined, 
as  they  commonly  are  in  mines,  with  some 
unmetallic  substance,  thev  are  said  to  be 
mineralized ;  the  substance  that  sets  them 


Fossils.  16f 

in,  that  state,  is  called  a  mineratizer,  and 
the  compound  of  both,  an  ore  ;  which  term 
is  applicable  when  stones,  or  earths,  con- 
tain metallic  substances,  \vhether  native  or 
mineralized,  in  a  notable  proportion. 

Several  metals  are  ductile  and  mallea- 
ble, and  their  parts  may  be  displaced  from 
each  other  by  compression,  or  hammer- 
ing, without  losing  their  cohesion.  Hence., 
some  of  them  may  be  stretched  out  to 
thin  laminae,  or  drawn  into  slender  fila- 
ments ;  as,  for  instance,  gold,  silver,  plan- 
tina,  copper,  lead,  tin,  and  iron. — Other 
metals  are  fragile,  or  brittle,  and  do  not 
admit  of  being  stretched  and  extended  ; 
such  are  antimony,  arsenic,  cobalt,  bis- 
muth, &Pc. 

All  metals  are  fusible,  but  not  all  in 
the  same  degree  ;  thus  mercury  is  mel- 
ued  even  by  the  usual  temperature  of  our 
atmosphere. — Some  metals,  as  tin  and 
^ead,  melt  even  before  ignition ;  others, 
as  silver,  gold  copper,  iron,  fuse  only  af- 
ter being  ignited. 

All  metals,  iron  and  platina  only  excep- 
ted,  melt  on  a  sudden,  as  soon  as  they 
are  heated  in  a  due  degree  ;  but  iron 
and  platina  grow  soft  before  they  fuse.. 


168  Fossils. 

and  on  this  depends  their  very  useful 
property  of  becoming  capable  of  being 
-welded. 

Almost  all  metals  may  be  combined 
by  fusion  into  one  seemingly  homogene- 
ous mass,  and  from  thence  various  metal- 
lic mixtures,  metallic  alloys,  or  composi- 
tions arise  ;  which,  for  their  particular 
properties,  are  often  of  very  great  utility. 

If  metals  be  continued  in  fusion,  the} 
lose  their  brilliancy,  and  become  an  opaque 
powder,  or  what  is  termed  a  metallic  oxyd 
or  calx. 

All  metals,  gold,  silver,  and  platina, 
excepted,  are  oxyded  or  calcined  in  fire 
with  access  of  air.  In  this  respect,  those 
•which  cannot  be  oxyed  by  fire  have  recei- 
.  ved  the  name  of  noble  metals,  to  distin- 
guish them  from  the  rest  which  may  be 
calcined  that  way,  and  are  called  base 
metals. 

Gold  is  a  noble  metal,  of  a  yellow  colour; 
and,  after  platina,  the  heaviest  of  metals. 
Its  specific  gravity  is  from  19,258  to  19,- 
640.  Its  hardness  and  elasticity  are  in- 
considerable ;  but  its  tenacity  is  great  ; 
and  with  regard  to  ductility,  or  malleabili- 
ty it  exceeds  all  other  metallic  substances. 


Fossils.  169 

Platma  is  a  noble  metal  of  a  white  co- 
lour ;  for  which  reason  some  called  it 
•white  gold.  In  Europe  it  is  known  only 
since  the  middle  of  the  present  century, 
and  brought  to  us  in  small  irregularly-fig- 
ured grains,  but  which  are  impure,  and 
mostly  contaminated  with  iron.  Pure 
platina  exceeds  all  other  metals,  even  gold 
In  specific  gravity,  which  is  found  to  reach 
21,061.  It  is  ductile  and  malleable  ;  its 
hardness  and  tenacity  are  greater  than 
those  of  gold,  and  it  admits  of  being 
welded. 

Silver  is  a  noble  metal,  of  a  white  color 
whose  specific  gravity  is  variable  from 
1O,474  to  10,542  ;  it  is  very  malleable 
and  ductile,  and  of  a  moderate  hardness. 
It  fuses  in  a  heat  of  less  intensity  than  is 
required  by  gold  ;  it  is  fixed  in  fire,  and  is 
not  affected  by  water  nor  air,  remaining 
in  both  unaltered  ;  but  by  sulphureous 
vapours  it  is  very  soon  tarnished. 

Mercury,  or  quicksilver  is  a  base  metal 
of  a  white  colour.  Its  specific  gravity  is 
upon  an  average  13,674 — it  is  the  most 
fusible  of  all  known  metals,  and  continues 
in  the  fluid  state  even  in  the  cold  temper- 
ature of  our  winters  j  it  congeals  only  at 


1 70  Fossils. 

40  Farenheit,  and  shews  then  some  tena- 
city and  ductility. 

Lead  is  a  base  metal  of  a  bluish  white 
colour.  Its  specific  gravity  is  from  11,- 
352  to  11,445  ;  it  is  considerably  ductile 
but  little  tenacious  and  hard,  hence  it  may 
be  extended  in  thin  plates  by  the  hammer 
but  not  drawn  into  fine  wire.  It  has 
scarcely  any  elasticity. 

Bismuth  is  a  yellowish  or  reddish  white 
metal,  of  a  foliated  fracture,  and  very 
brittle,  it  being  even  reducible  to  powder 
by  the  hammer.  Its  specific  gravity  is 
from  9,670  to  9,822.  It  is  somewhat 
harder  than  lead  but  more  fusible. 

Nickel  is  a  greyish  white  metal,  of  a 
specific  gravity  between  9,OOO  and  9,333 
It  is  malleable,  and  very  compact  or  firm. 

Copper  is  a  base  metal,  of  a  brownish 
red  colour ;  sonorous,  very  tenacious, 
ductile,  and  malleable  ;  of  a  considerable 
compactness ;  of  a  moderate  hardness 
and  elasticity  ;  and  of  an  hackly  fracture. 
Its  specific  gravity  varies  from  7,788  to 
9,000. 

Arsenic  is  a  brittle  metal,  and  on  the 
recent  fracture,  of  a  mean  colour,  betwixt 
tin- white  and  lead-grey  ;  but,  on  expo- 


Fossils.  in 

sure  to  air,  it  soon  turns  black  and  dull. 
Its  specific  gravity  is  8,310;  its  hardness 
is  somewhat  considerable,  and  seemingly 
surpassing  that  of  copper.  But  its  duc- 
tility is  so  little,  and  its  brittleness  so  great 
that  it  is  readily  converted  into  powder  by 
the  hammer. 

Of  all  metals  Iron  exhibits  the  most 
varieties  and  deviations.  Its  differences 
in  colour,  density,  fracture,  tenacity,  duc- 
tility, and  degree  of  fusibility,  are  uncom- 
monly great. — Soft  and  malleable  iron  has 
a  greyish-white^  colour,  a  light  grey,  fi- 
brous,hackly  fracture.  Its  specific  gravity 
at  a  mean  rate  is  7,700 ;  its  hardness  is 
not  great,  but  its  malleability  and  tenaci- 
ty are  considerably  so  ;  and  it  has  this 
characteristic  property,  not  possessed  by 
other  species  of  this  metal,  that  whether 
cold  or  ignited,  it  may  be  extended,  forg- 
ed, and  bent,  without  breaking. 

By  cast  or  crude  iron,  that  metal  is 
understood,  which  is  obtained  by  the 
first  smelting  of  iron-ores.  Such  iron  is 
distinguished  from  ductile  iron  by  its  re- 
fusing to  be  extended  and  forged  by  the 
hammer,  whether  cold  or  ignited,  by  its 
brittleness ,aud  by  its  fusing  in  strong  heat 


172  Fossils. 


in  open  fire,  without  addition,  whereby 
it  is  rendered  capable  of  being  cast  into 
moulds.  The  colour  of  crude  iron  is 
more  or  less  of  a  pale  grey. 

Steel  differs  from  both  the  ductile  and 
the  crude  iron. — Its  distinguishing  pro- 
perty is,  that  when  it  is  tempered^  that 
is  to  say,  when  it  is  hastily  plunged  in 
cold  water  while  ignited  to  redness,  it  be- 
comes harder,  more  brittle,  and  inflexi- 
ble ;  and  that,  before  this  tempering  or 
hardening,  it  is  ductile,  whether  cold  or 
ignited  ;  and  also,  that  after  having  been 
hardened,  it  reassumes  its  ductility  by  a 
fresh  igniton  and  gradual  cooling,  with- 
out quenching. — Its  colour  is  a  light  grey, 
its  fracture  finely  granular. 

Cobalt  is  a  base  metal,  of  a  lead  grey 
colour,  brittle  and  hard,  and  of  specific 
gravity  from  7,000  to  7,700.  This  metal 
is  rather  of  difficult  fusion. 

Tin  is  a  base  metal  of  a  white  colour, 
a  little  more  verging  to  blue  than  that  of 
silven — -It  is  very  soft,  pretty  malleable 
and  tractable  ;  its  compactness  and  elas- 
ticity are  but  slight.  When  broken  or 
bent,  or  when  compressed  betwen  the 
teeth,  it  makes  a  peculiar  crackling  noise7 


Fossils*  173 

which  is  one  of  its  characteristic  proper-* 
toes.  The  specific  gravity  of  tin  is  varia- 
ble from  7,216  to  7,331.  Its  gravity  de- 
creases in  the  ratio  of  its  purity. 

Zinc  is  a  white  metal,  of  a  radiated 
texture,  changing  into  the  foliated*  It  is 
of  a  middle  kind  betwen  the  malleable 
and  brittle  metals,  and  may  be  extended 
into  thin  laminae,  at  least  between  metal- 
lic cylinders  in  rolling  mills.  The  spe- 
cific gravity  of  this  metal  is  from  6,862 


Antimony  has  a  white  colour,  resem- 
bling that  of  tin,  a  foliated  radiated  text- 
ure, and  is  very  brittle.  Its  specific  gra- 
vity varies  from  6,702  to  6,860.  In  the 
air  it  loses  little  of  its  metallic  splendour 
and  it  does  hot  rust  in  the  strict  sense  of 
the  word. 

Manganese  is  a  white,  hard,  brittle  me- 
tal, whose  specific  gravity  is  found  to  be 
from  6,850  to  7,OOO. 

Molybdena  has  a  pale  lead-grey  colour, 
a  metallic  lustre,  and  a  laraellated  fracture 
it  is  very  soft,  and  marks  paper  easily, 
leaving  a  shining  trace.  Its  specific  gra- 
vity is  between  4,138  and  4,569. 

Wolfram  is  a  metallic  substance  of  modr 
P 


Fossil*. 

ern  discovery,  and  of  a  particular  kind, 
whose  calx  or  oxyd  is  of  a  yellow  colour, 
and  one  of  the  constituent  parts  of  the  fos- 
sil, called  tungsten. 

Another  distinct  metallic  substance  on- 
ly a  few  years  since  discovered  by  Klap- 
roth,  is  the  Uranium.  The  oxyd  of  u- 
ranium  has  a  lemon-yellow  colour,  is  fix- 
ed in  fire,  and  infusible  when  alone.  Ig- 
nition changes  its  colour  to  a  brownish 
grey. 

We  are  likewise  indebted  to  Klaproth 
for  the  discovery  of  the  new  metal  called 
by  him  Titanium  or  Titanite. — It  is  con- 
tained in  the  mineral  called  red  shoerl  as 
a  native  oxyd.  The  colour  of  the  perfect 
oxyd  of  titanium  is  red  ;  but  when  kept 
In  violent  ignition  upon  coals,  and  by  a 
greater  degree  of  disoxydation,  it  gradu- 
ally assumes  a  yellowish,  bluish,  and 
blackish  hue. 

Tellurium  is  a  metal  of  a  white  colour 
like  tin, inclining  to  lead-grey.  It  is  brittle 
and  friable  ;  possesses  a  lamellar  texture, 
and  considerable  metallic  lustre  ;  is  one 
of  the  most  easily  fusible  metals,  and  ex- 
hibits a  crystallized  surface  when  slowly 
cooling  after  fusion.—- Its  specific  gravity 
is  6,1 15. 


fossils.  175 

Chrome  is  a  white  metal,  inclining  to 
grey,  very  brittle,  and  crystallizable  at  an 
elevated  temperature  in  feathered  fila- 
ments on  the  surface. 

The  minerals  to  be  found  in  England 
are  both  curious  and  useful.  Amber,  jety 
vitriol  and  allum  are  found  in  considera- 
ble quantities  ;  our  canal  coal  approaches 
nearly  to  the  beauty  of  jet,  and  even  our 
common  coal  fire  for  firing  is  of  a  superior 
nature.  The  English  earth  and  gravel 
are  of  the  best  quality;  and  we  have  stone,, 
slates,  flags,  and  other  fossils  necessary 
for  building  in  great  abundance.  Tin  is 
another  article  in  which  England,  from 
the  time  of  the  Phenicians  had  always  had 
the  pre-eminence-  The  county  of  Corn- 
wall alone  produces  more  than  all  the 
world  besides.  Our  lead  ore  is  richer 
than  in  other  countries,  runs  more  fluently 
in  the  fire,  require^  less  trouble  and  ex- 
pense in  working,  and  is  when  wrought 
very  fine  and  ductile*  Our  black  lead  or 
wadd,  found  in  Cumberland,  is  a  mineral 
of  great  use  and  value  in  several  branches 
of  trade  and  arts.  Copper  and  iron  are 
also  found  here  in  great  plenty,  and  seve* 


176 


Fossils. 


ral  ores  of  these  metals,  particularly  in 
Anglesey,  have  of  late  been  discovered, 
and  brought  into  use,  which  were  un- 
known before  the  recent  improvements  in 
chemistry. 


Plants* 


.  X. 

Of  Vegetables  or  Plants 

NEXT  to  the  earth  itself,  we  may  con- 
sider those  that  are  maintained  on  its 
surface  ;  which  though  they  are  fastened 
to  it,  yet  are  very  distinct  from  it  :  and 
those  are  the  whole  tribe  of  vegetables 
or  plants.  These  may  be  divided  into 
three  sorts,  herbs,  shrubs^  and  trees. 

Herbs  are  those  plants,  whose  stalks 
are  soft,  and  have  nothing  woody  in  them, 
as  grass,  sowthistle,  and  hemlock.  Shrubs 
and  trees  have  all  wood  in  them  ;  but 
with  this  difference,  that  shrubs  grow 
not  to  the  height  of  trees,  and  usually 
spread  into  branches  near  the  surface  of 
the  earth  ;  whereas  trees  generally  shoot 
up  in  one  great  stem  or  body,  and  then, 
at  a  good  distance  from  the  earth,  spread 
into  branches  ;  thus,  gooseberries  and 
currants,  are  shrubs  ;  oaks  and  cherries, 
are  trees. 

P2 


Plants. 

Numerous  are  the  works  which  have 
been  written,  especially  in  later  times,  on 
the  science  -of  botany,  and  various  sys- 
tems, or  classifications  of  plants  have 
from  time  to  time  been  proposed;  but 
the  sexual  system  of  Linnaeus  is  at  pre- 
sent generally  received.  This  naturalist 
has  cjrawn  a  continued  analogy  between 
the  vegetable  economy  and  that  of  the 
animal ;  and  has  derived  all  his  classes, 
orders,  and  genera,  from  the  number, 
situation,  and  proportion  of  the  parts  ot 
fructification.  In  twenty-four  classes, 
he  has  comprehended  every  known  genus 
and  species.  In  considering  a  plant 
with  a  view  to  its  characteristics,  or  dis- 
tinguishing features,  it  is  divided  by  Lin- 
naeus into  the  following  parts,  making  so 
many  outlines,  to  which  the  attention  o£ 
the  botanical  observer  must  be  directed  ; 
1.  Root ;  2.  Trunk  ;  3.  Leaves  ;  4.  Props 
5.  Fructification  ;  6.  Inflorescence.  1* 
The  root  consists  of  two  parts,  the  caudex 
and  the  radicula.  The  caudex,  or  stump, 
is  the  body  or  knob  of  the  root  from  which 
the  trunk  and  branches  ascend,  and  the 
fibrous  roots  descend,  and  is  either  solid, 
bulbous,  or  tuberous  5  solid,  as  in  trees* 


Plants.  179 

and  other  examples  ;  bulbous,  as  in  tulips 
&c.  tuberous,  as  in  potatoes,  &c.  The 
radicula  is  the  fibrous  part  of  the  root, 
branching  from  the  caudex.  2.  The  trunk, 
•which  includes  the  branches,  is  that  part 
which  rises  immediately  from  t\ir  caudex 
in  either  herbaceous,  shrubby,  or  arbor- 
escent, and  admits  of  several  other  dis- 
tinct! ons,according  to  its  shape,substance, 
surface,  &?c.  3.  The  leaves  are  either 
sirs  pie,  as  those  that  adhere  to  the  branch 
singly,  or  compound,  as  when  several  ex- 
pand from  one  footstalk.  Leaves  are  far- 
ther described  by  various  terms  indicative 
of  their  form  and  outline.  4.  The  props 
those  external  parts  which  strengthen 
support,  or  defend,  the  plants  on  which 
they  are  found,  or  serve  to  facilitate  some 
necessary  secretion  ;  as  the  petlious,  or 
footstalk  of  the  leaf;  the  pedunculus,  or 
footstalk  of  the  flower,  the  stipula,  or 
husk,  that  is,  the  small  leaves  that  gener- 
ally surround  the  stalk  at  its  divisions  ; 
the  cirrfiU8,or  tendril;  ihepubes,  or  down; 
the  arma,  or  defensive  weapon,  as  thorns* 
5.  The  fructification,  or  mode,  of  fruit- 
bearing.  6.  The  inflorescence,  or  mode  by 
which  the  flowers  are  joined  to  the  seve- 
ral peduncles. 


180  Plants. 

In  plants  there  is  an  infinite  diversity; 
some  aquire  a  long  succession  of  ages  to 
bring  them  to  perfection,  while  others  at- 
tain their  full  maturity  in   a  few  hours  ; 
some  are  of  immense  magnitude,  while 
others  are  of  an  inferior  stature,  descend- 
ing by  gradation  till  they  become  too  mi- 
nute to  be  cognizable  by  the  senses.  The 
mighty  baobob  of  Senegal,  described  by 
Adanson,whose  stem  is  75  feet  in  circum- 
ferance,  stands  a  stately  monument  on  the 
face  of  the  earth  for  many  thousands  of 
years ;    while  the   mushroom,  which   it 
much  resembles  in  form,  springs  up  in  a 
day,  perfects  its  seeds,  and  is  withered  to- 
morrow ;  and  when  we  carry  our  views 
still  farther,  into  that  immense  profound 
of  minuteness  which  has  but  of  late  been 
partly  laid  open  to  us  by  the  invention  of 
the  microscope ;  into  the  class  of  mosses, 
which  are  in  some  measure  cognizable  by 
the  naked  eye,  and  still  farther  into  the 
more  minute  class  of  plants  denominated 
mould,  which,  even  in  those  of  the  largest 
species,  are  too  small  to  have  their  parts 
cognizable  by  the  naked  eye,  and  which, 
when  viewed  by  the  best  microscopes, 
discover  a  series  of  existences  diminish 


Plants.  181 

ing  by  a  regular  gradation,  like  stars  in 
the  galaxy  under  the  best  telescopes,  till 
they  are  lost  in  the  infinity  of  minuteness, 
leaving  every  reason  to  believe,  that, 
could  the  magnifying  powers  of  our  in- 
struments be  augmented  a  thousand  fold, 
we  should  still  find  ourselves  as  far  from 
discovering  the  termination  of  this  series 
of  infinite  diminution  as  we  were  at  the 
commencement  of  our  imperfect  survey. 
The  world  that  we  see,  therefore,  seems 
to  be  but  a  very  small  part  of  that  which 
exists  ;  our  feeble  optics  are  capable  of 
taking  in  scarcely  a  point  of  that  universe 
which  surrounds  us  ;  and  our  imperfect 
understandings  can  scarcely  obtain  a 
glimpse  of  that  infinite  power  and  wisdom 
which  regulates  the  whole.  Among  this 
infinity  of  objects,  however,  we  can  clear- 
ly perceive  the  most  perfect  regularity 
and  order  pervading  every  part;  and 
that  all  the  operations  of  nature  proceed 
with  invariable  steadiness  to  effect  the 
purposes  for  which  they  have  been  de- 
signed. 

Thus  we  see  that  all  animate  objects, 
from  the  largest  that  has  been  discovered 
on  this  globe,  to  the  smallest  that  can 


182  Plants. 


ever  be  made  to  be  perceptible  to  us,  in- 
variably proceed  from  other  animated  ob- 
jects of  the  same  kind,  although  they  ap- 
pear at  times  under  such  disguised  forms 
as  not  to  be  at  first  sight  cognizable  by  us. 
This  rule  applies  to  vegetables  as  well  as 
animals.  The  plant  of  mould,  which, 
even  when  it  hath  attained  its  full  stature, 
can  scarcely  be  perceived  as  a  point  under 
our  microscopes  of  the  highest  magnify- 
ing power,  we  have  every  reason  to  be 
satisfied,  produces  its  seeds  in  as  regu- 
lar order,  which  ripen  at  their  appointed 
period  with  the  same  regularity  as  those 
of  the  mighty  baobob  ;  but  while  this  re- 
mains a  stately  monument  upon  the  sur- 
face of  this  earth,  and  sees  thousands  of 
generations  of  men  succeed  each  other, 
and  successively  shelter  themselves  un- 
der the  protecting  shade  of  its  spreading 
branches,  we  observe  the  mould  spring  up, 
perfect  its  seeds,  scatter  them  in  imper- 
ceptible myriads  in  the  air,  and  disap- 
pear within  the  short  space  of  one  hour  : 
so  that  during  the  short  period  of  our 
existence  here  many  myriads  of  genera- 
tions of  mould  have  succeeded  each  other. 
Time  itself  then,  when  the  universe  is 


Plants.  183 

viewed  as  a  whole,  can  only  be  consider- 
ed as  a  relative  object.  Shall  man  then, 
a  being  who  cannot  comprehend  fully  the 
nature  of  a  single  object  around  him, 
dare  proudly  to  lift  up  his  face,  and  pre- 
tend to  decide  concerning  possibilities 
and  the  powers  of  nature !  His  proper 
province  is  to  be  humble  and  adore ! 

The  plants  with  which  we  are  best  ac- 
quainted may  be  arranged  into  three 
grand  divisions.  The  first  are  those 
whose  roots  and  stems  remain  for  many 
years,  which  comprehends  all  the  varie- 
ties of  trees  and  shrubs.  These,  for  the 
most  part,  require  several  years  to  bring 
them  to  a  state  of  puberty  (if  that  phrase 
may  be  admitted)^  when  they  begin  to 
put  forth  flowers,  and  perfect  their  seeds ; 
after  which  time  they  usually  continue 
to  produce  an  annual  crop  of  flowers  and 
seeds  for  a  long  period  of  time  ;  the  fruit 
in  general  succeeding  the  flowers,  and 
perfecting  their  seeds  in  the  same  year ; 
but  to  this  rule  there  are  several  excep- 
tions. In  a  few  instances  the  seeds  do 
not  attain  to  muturity  in  the  same  sea- 
son that  the  flower  is  produced ;  but? 
continuing  upon  the  tree  the  whole  win* 


184  Plants. 

ter  in  an  immature  state  without  being 
killed,  they  advance  in  the  second  season, 
and  then  only  perfect  their  seeds;  instances 
of  which  are  to  be  found  in  the  juniper 
and  orange-tree.  Others  continue  to  ad- 
vance for  several  years,  as  usual,  with- 
out showing  fruits ;  and  when  at  length 
they  reach  that  state  of  maturity,  they 
then  flower,  and,  having  perfected  their 
seeds,  they  decay  and  flower  no  more, 
dying  down  like  annual  plants  ;  an  exam- 
ple of  which  is  to  be  found  in  the  cab- 
bage-tree of  tropical  regions.  Some  are 
scarcely  ever  (perhaps  never)  known  to 
produce  either  flowers  or  seeds  of  any 
sort,  but  admit  of  being  propagated  by 
some  other  means  ;  instances  of  which 
are  to  be  found  in  the  English  elm  of  our 
own  country,  the  jack,  or  bread-fruit  tree 
of  India  ;  and  many  others. 

The  second  division  of  plants  are- those 
that  have  a  perennial  root,  from  which 
stalks  are  sent  forth  annually,  which  us- 
ually produce  flowers,  perfect  their  seeds 
in  the  summer,  and  die  down  to  the 
ground  at  the  approach  of  winter.  The 
stems  of  these  are  for  the  most  part  of  a 
similar  structure  and  consistence  with 
those  of 


Plants.  18* 

The  third  class,  or  annuals,  from  the 
seeds  of  which,  if  sown  in  the  spring^ 
stalks  spring  up  which  produce  flowers 
and  seeds  the  same  season ;  after  the 
perfecting  of  which  the  stalks  decay  and 
die  entirely  away.  Biennials  can  only 
be  viewed  as  a  diversity  of  these,  that 
have  not  sufficient  length  of  season  to 
bring  them  to  perfection  in  one  year. 

Whether  distinctions  similar  to  these 
take  place  among  those  minute  tribes  of 
plants  which  we  call  microscopical,  it 
exceeds  our  power  at  present  to  deter- 
mine. From  the  short  period  of  their 
existence,  we  have  been  generally  in- 
clined to  think  that  they  are  all  similar 
in  quality  to  annuals  ;  that  is  to  say,  that 
they  flower  but  once,  and  die  down  im- 
mediately after  they  have  once  perfected 
their  seeds*  Yet,  who  dares  pretend  to 
say,  that  the  plant  of  mould ^  which  ex- 
ists perhaps  but  one  of  our  hours,  may 
not  produce  in  that  period  many  thou- 
.sands  of  successions  of  ripe  seeds,  each 
of  which  has  taken  its  due  season  to  ri- 
pen like  those  of  the  baobob,  which 
flourishes  on  our  globe  for  hundreds  of 
ages!  for  the  same  infinite  power  which 


1&6  Plants. 


has  decreed   that  the  total  duration  o 
this  plant  shall  be    Jimited  to  an  hour, 
mny  have  also  decreed,  that  the  matura- 
tion of  its  seeds,  and  the  com-  lotion  of  a 
period  that  to  it  should  be  similar  to  that 
of  our  year,  should  be  accomplished  i 
the   thousandth  part  of  a  second  of  ou 
time. 

All  plants  seem  to  grow   in  the  sam 
manner:  the  genial   warmth  of  the  sun 
the  refreshment  of  the  rains,  the   sam 
soils  appear  t-->   suit  their  respective  spe 
cies  ;  and,        ?ha  superficial  glance,  the 
srem  to  have  the  same  common  parts 
chemical  analysis  discovers  the  same  con- 
stiturnt  principles  in  all,  that  is  to  say 
calcareous  earth,  oil,  water,  and  air,  wit" 
a  portion  of  iron,  to  which  they  ovvethei 
beautiful  colours.     Yet,  although  compo- 
sed of  similar  materials,  their  juices  to 
the  eye,  and  to  the  taste,  appear  as  vari- 
ous as  their  forms.     The  soporific  milk 
oi  the  poppv  ,  the  acrid  but  equally  milky 
juice  of  the  spungc,  the  acid  of  the  sorrel, 
the  saccharine  sap  of  the   sycamore  and 
mapie,  and  the  resin  of  the  tribe  of  pines-, 
bear  no  resemblance  to  each  other. 

The  inward  structure  of  plants  is  as 


i 


Plants.  187 

regular  and  various  as  their  external 
forms  are  elegant  and  well-proportioned. 
The  root,  trunk,  branch,  leaf,  flower, 
fruit  and  seed,  have  each  its  peculiar 
character  and  form.  No  part  in  the  con- 
texture of  the  smallest  fibre  is  unfinish- 
ed but  is  formed  with  the  most  minute 
exactness.  The  seeds  of  plants  have  the 
appearance  of  shells,  unlike  in  form,  and 
diversified  with  spots  and  stripes.  Eve- 
ry seed  possesses  a  reservoir  of  nutri- 
ment, designed  for  the  growth  of  the 
future  plant.  This  is  the  matter  prepar- 
ed by  nature  for  the  reproduction  and 
continuation  of  the  whole  species.  This 
nutriment  consists  of  starch,  mucilage, 
or  oil,  within  the  coat  of  the  seed,  or  of 
sugar  and  subacid  pulp  in  the  fruit,  which 
belongs  to  it.  The  sections  of  the  vaii- 
ous  kinds  of  trees  are  crossed  with  the 
greatest  number  of  regular  figures  which 
the  imagination  can  conceive.  The  lines, 
which  form  the  texture  of  fir-trees, 
are  distant ;  but  those  of  oak  are  close 
and  compact. — And  this  difference  of 
texture  may  serve  to  account  for  their 
greater  or  less  solidity,  and  the  difference 
of  time  requisite  for  them  to  arrive  at 
maturitv. 


188  Plants. 

The  nourishment  of  plants  is  perform 
ed  chiefly  by  the  tender  fibres  of  the  roots, 
•which  being  spread  under-ground,  im- 
bibe from  the  moist  earth  juice  fit  for 
their  nutriment,  which  they  transmit  to 
the  other  parts.  The  impulse  by  which 
the  juices  rise  seems  to  be  capillary  at- 
traction ;  for  the  roots  of  all  vegetables 
are  supposed  but  bundles  of  capillary 
tubes  :  and  whether  we  consider  earth, 
water,  salt  and  oil,  as  the  food  of  plants — - 
or,  with  Kirwan,  that  coal  is  essential  to 
that  food — or  with  Ingenhouz,  that  it  is 
vital  air  decomposepl  into  fixt  air  and 
azote  ;  still  that  food  must  be  formed  by 
water  into  an  emulsion,  capable  of  being- 
acted  upon  by  capillary  attraction  ;  and 
as  all  roots  are  but  assemblages  of  these 
tubes,  there  can  be  little  doubt  but  their 
attraction  supplies  the  plant  with  its  first 
food  ;  though  other  causes  must  assist 
in  carrying  it  to  the  tops  of  the  tallest 
trees,  such  as  dilatation  and  contraction, 
by  the  successive  heat  and  cold  of  day 
and  night,  the  muscular  action  of  vascu- 
lar rings  round  the  tubes  irritated  to  con- 
traction by  the  stimulant  sap,  &c.  The 
anterior  bark  conducts  the  nourishment 
supplied  by  the  earth. 


, 


Plants.  180 


After  the  sap  has  thus  ascended  to  the 
eaves,  it  there  undergoes  certain  altera- 
tions, and  is  converted  into  another  fluid, 
called  the  succus  proprhis,  or  peculiar 
juice  ;  which,  like  the  blood  in  animals^ 
is  afterwards  employed  in  forming  the- 
various  substances  found  in  plants.  The 
leaves  may  therefore  be  considered  as 
the  digesting  organs  of  plants,  and  as 
equivalent  in  some  measure  to  the  sto- 
mach and  lungs  of  animals.  The  leaves 
consequently  are  not  mere  ornaments  ; 
they  are  the  most  important  parts  of  the 
plant.  Accordingly  we  find,  that  when- 
ever we  strip  a  plant  of  its  leaves,  we 
strip  it  entirely  of  its  vegetating  powers 
till  new  leaves  are  formed  ;  for  when  the 
leaves  of  plants  are  destroyed  by  insects, 
they  vegetate  no  longer,  and  their  fruit 
never  makes  any  further  progress  in  ri- 
pening, but  decays  and  dries  up, 

Leaves  on  one  side  draw  nutriment 
from  the  air,  and  perspire  on  the  other ; 
for  plants,  as  well  as  animals,  perspire, 
and,  in  both  cases,  this  function  is  essen- 
tial to  health.  The  quantity  they  per- 
spire varies,  according  to  the  extent  of 
the  surface  from  which  it  is  emitted,  the 


temperature  of  the  air,  the  time  of  the 
day,  and  the  humidity  of  the  atmosphere. 
Leaves  form  the  greatest  part  of  the  sur- 
face, and  it  is  found  that  the  quantity  of 
these  very  materially  affect  the  quantity  of 
perspiration  ;  and  this  process  is  increas- 
ed or  diminished,  chiefly,  in  proportion 
to  the  increase  or  diminution  of  the  fo- 
liage of  vegetables.  The  degree  of  heat 
in  which  the  plant  is  kept  also  varies  the 
quantity  of  matter  perspired  ;  this  being 
greater,  in  proportion  to  the  greater  heat 
of  the  surrounding  atmosphere.  The 
degree  of  light  has  likewise  considerable 
influence  in  this  respect ;  for  plants  uni- 
formly perspire  most  in  the  forenoon, 
though  the  temperature  of  the  air,  in 
•which  they  are  placed,  should  be  unvari- 
ed. A  plant  also  exposed  to  the  rays  of 
the  sun,  has  its  perspiration  increased  to 
a  much  greater  degree  than  if  it  had 
been  exposed  to  the  same  heat  under  the 
shade.  Finally,  the  perspiration  of  veg- 
etables is  increased  in  proportion  as  the 
atmosphere  is  dry,  or,  in  other  words, 
diminished  in  proportion  as  the  atmos- 
phere is  humid.  The  more  vigorous 
and  healthy  the  plant,  the  more  copious 
the  perspiration  j  this  function,  like  the 


Plants.  191 

est,  depending  much  on  the  vital  ener- 
rgy.  Excessive  perspiration  seems  to 
hurt,  and  even  sometimes  to  destroy,  veg- 
etables ;  defective  perspiration  is  equal- 
ly injurious.  It  is  also  found,  that  this 
function  is  performed,  chiefly,  if  not  al- 
together, by  the  leaves  and  young  shoots* 
That  it  may  be  properly  carried  on,  all 
leaves  are  deciduous  ;  in  those  trees  cal- 
led ever-greens,  there  being  a  constant 
succession  of  leaves,  to  prevent  the  or- 
gan of  perspiration  from  becoming  rigid* 
A  quantity  of  moisture  is  absorbed  by 
plants,  when  exposed  to  a  humid  atmos- 
phere. This  absorption,  as  well  as  the 
perspiration,  is  performed  by  the  leaves  $ 
but  in  what  manner  has  not  yet  been  as- 
certained. Experiments  made  by  M, 
Guettard  shew,  that  perspiration  is  more 
considerable  from  the  upper,  than  from 
the  under,  surface  of  the  leaves. 

Plants  in  general  are  known  to  receive 
and  transpire  more,  in  equal  time,  than 
large  animals.  It  has  been  found  by  ac- 
curate calculation,  and  repeated  experi- 
ments, that  a  plant  of  the  sun-flower  re- 
ceives and  perspires  in  twenty-four  hours 
seventeen  times  more  than  a  man, 


192  Plants. 

Some  botanists  have  conceived  that 
plants,  as  well  as  animals,  have  a  regular 
circulation  of  their  fluids.  Others  thinfc 
this  very  improbable.  On  both  sides, 
recourse  has  been  had  to  experiments, 
and  from  these  conclusions  perfectly  op- 
posite have  been  deduced ;  so  that  no 
certain  conclusion  can  be  drawn  on  this 
head. 

Light  has  great  effect  on  vegetation. 
Plants  that  grow  in  the  shade,  or  in  dark- 
ness, are  pale,  and  without  colour  ;  and 
the  more  they  are  exposed  to  the  light, 
the  more  colour  they  acquire. 

Vegetables  are  not  only  indebted  to 
light  for  their  colour  ;  their  taste  and 
odour  are  derived  from  the  same  source. 
Hence  it  happens  that  hot  climates  are 
the  native  countries  of  perfumes,  odori- 
ferous fruits,  and  aromatic  resins. 

The  action  of  light  on  the  organs  of 
plants,  causes  them  to  pour  out  streams 
of  pure  air  from  the  surfaces  of  their 
leaves,  while  exposed  to  the  sun  ;  where- 
as, on  the  contrary,  when  in  the  shade, 
and  at  night,  they  emit  air  of  a  noxious, 
quality. 

The  various  secretions  of  vegetables^ 


Plants.  193 

as  of  odour,  fruit,  gum,  resin,  wax,  hon- 
ey, &c.  seem  brought  about  in  the  same 
manner  as  in  the  glands  of  animals  ;  the 
tasteless  moisture  of  the  earth  is  convert- 
ed by  the  hop-plant  into  a  bitter  juice  ; 
as  by  the  caterpillar  in  the  nutshell  the 
sweet  kernel  is  converted  into  a  bitter 
powder.  While  the  power  of  absorption 
in  the  roots  and  barks  o£  vegetables  is 
excited  into  action  by  the  fluids  applied 
to  their  mouths  like  the  lacteals  and  lym- 
phatics of  animals. 

The  individuals  of  the  vegetable  world 
may  be  considered  as  inferior  or  less 
perfect  animals  ;  a  tree  is  a  congeries  of 
many  living  buds,  and  in  this  respect  re- 
sembles the  branches  of  coralline,  which 
are  a  congeries  of  a  multitude  of  ani- 
mals. Each  of  these  buds  of  a  tree  has 
its  proper  leaves  or  petals  for  lungs,  pro- 
duces its  viviparous  or  its  oviparous  off- 
spring in  buds  or  seeds  ;  has  its  own 
roots,  which  extending  down  the  stem  of 
the  tree  are  interwoven  with  the  roots  of 
the  other  buds,  and  form  the  bark,  which 
is  the  only  living  part  of  the  stem,  is  an- 
nually renewed,  and  is  superinduced  up- 
on the  former  bark,  which  then  dies,  and 


194  Plants. 

with  its  stagnated  juices  gradually  hard- 
ening into  wood  forms  the  concentric 
circles,  which  we  see  in  blocks  of  timber, 
which  annual  rings  serve  as  natural  marks 
to  distinguish  the  age  of  trees. 

The  botanist  follows  nature  into  her 
most  retired  abodes,  and  views  htr  in 
her  simple  state,  and  native  m^-stv. 
He  remarks  some  of  her  productions 
figured  by  cultivation  in  gardens,  wh 
amid  all  the  varieties  of  thr  apple  and 
the  pear?  however  distinguished  by  th^ir 
colour,  size  and  taste,  he  observes,  that 
there  is  but  one  original  species  c;f  each, 
and  that  they  have  respectively  but  one 
radical  character.  He  beholds  the  won- 
derful prodigality  of  nature,  even  in  the 
composition  of  the  common  daisy,  which 
consists  of  more  than  two  hundred  flow- 
ers, each  including  its  respective  corolla, 
germ,  pistil,  stamina,  and  seed,  as  per- 
fectly formed  as  those  of  a  complete  lily, 
or  hyacinth.  And  he  sees  this  diversity 
as  fully  illustrated  in  the  different  sorts 
of  grass,  a  term  which,  although  it  com- 
monly conveys  only  one  notion  to  tfae  Vul- 
gar mind,  and  one  object  to  the  undis- 
ce^rning  eye,  consists  of  five  hundred  dif- 


Plants.  195 

ferent  species,  each  formed  with  infinite 
beauty  and  variety.  From  others  he  par- 
ticularly distinguishes  the  elegant  brizct 
media,  so  common  in  the  fields,  and  so 
remarkable  for  its  delicate  hair-like  stem, 
trembling  at  every  breeze  ;  the  anthoxan- 
ihum  odoratum,  which  gives  its  fragrance 
to  the  new-mown  hay ;  and  the  stipa 
pennata  with  its  waving  plumes  resem- 
bling the  feathers  of  the  bird  of  paradise* 
The  botanist  enjoys  a  pleasing  and  inno- 
cent amusement,  most  agreeably  com- 
bined with  a  love  of  rural  retirement, 
and  which  gives  a  new  and  growing  inter- 
est to  every  wralk  and  ride,  in  the  most 
delightful  season  of  the  year.  Indeed 
man  cannot  contemplate  the  vegetable 
creation  without  recalling  the  idea  of 
beauty,  sweetness,  and  a  thousand  charms 
that  captivate  the  senses.  The  perfume 
of  the  rose  and  the  stately  magnificence 
of  the  forest  successively  catch  his  atten- 
tion and  delight  him* 

The  number  of  species  of  plants  alrea- 
dy known  is  about  twenty-five  thousand  ; 
and  botanists  suppose  that  double  that 
number,  at  least,  remain  to  be  discoveredo 

The  different  vegetable  productions  are 


196  Plants 

no  less  useful  than  numerous.  The  pur- 
poses to  which  the  trees  of  Britain  are  ap- 
plied are  well  known,  from  the  flexible 
willow,  which  forms  the  basket,  to  the 
hardy  oak,  which  composes  the  most  sub- 
stantial parts  of  a  ship  of  war,  guards  the 
British  islands  from  foreign  invasion,  and 
displays  to  the  most  remote  countries  the 
greatness  of  our  maritime  power.  All 
possess  different  qualities,  adapted  to 
their  different  purposes.  The  meanest, 
and  in  their  appearance  the  most  unplea- 
sant, have  their  use  ;  even  the  thistle  is 
not  only  the  food  of  some  animals,  but  is 
serviceable  in  making  glass.  There  is 
scarcely  a  plant  which  although  rejected 
as  food  by  some  animals  is  not  eagerly 
sought  by  others.  The  horse  yields  the 
common  water  hemlock  to  the  goat,  and 
the  cow  the  long-leafed  water  hemlock  to 
the  sheep.  The  goat  again  leaves  the 
aconite,  or  bane-berries  to  the  horse* 
The  euphorbia  or  spurge,  so  noxious  to 
man,  is  greedily  devoured  by  some  of  the 
insect  tribes.  The  aloe  is  a  magazine  of 
provisions  and  of  implements  to  the  In- 
dians who  inhabit  the  banks  of  the  Ohio 
and  the  Missisippi.  Some  plants,  a* 


Plants.  19? 

rhubarb  and  opium,  alleviate  the  tortures 
of  pain  ;  and  some,  as  the  quinquina,  or 
Peruvian  bark,  can  subdue  the  rage  ot  the 
burning  fever.    Wheat,  the  delicious  and 
prolific   grain  which  gives  to  the  inhabi- 
tants of  the  northern  world  their  whole- 
some nutriment,  grows  in  almost  every 
climate,     Where  excessive  heat  or  other 
causes  prevent  it  from  cojning  to  perfec- 
tion, its  place  is  amply  supplied  by  the 
bread-fruit,  the  cassavi-root  and  maize, 
and  more  particularly  by  rice,  which  is  the 
common  aliment  of  that  great  portion  of 
mankind  who  inhabit  the   warm  regions 
of  the  earth.     Every  meadow  in  the  ver- 
nal season  brings  forth  various  kinds  oi 
grass ;  and   this   spontaneous  and    most 
abundant  of  all  vegetable  productions  re- 
quires only  the  labour  of  the  husbandman 
to  collect  its  harvest.     The   iron-wood^ 
solid  as  marble,  furnishes  the  Otaheitean 
with  his  long  spear  and  massy  club.  The 
wild  pine  of  Campeachy  retains  the  rain- 
water in  its  deep  and  capacious  leaves  not 
less  for  the  refreshment  of  the  tree  itself, 
than  of  the  thirsty  native  of  a   burning 
soil.     The  cocoa  of  the  East  and  West 
Indies  anwers  many  of  the  most  usetul 
R 


198  Plants. 

purposes  of  life  to  the  natives  of  a  warm 
climate.  Its  bark  is  manufactured  into 
cordage  and  clothing,  and  its  shell  into 
useful  vessels  ;  its  kernel  affords  a  pleas- 
ant and  nutritive  food,  and  its  milk  a  cool- 
ing beverage  ;  its  leaves  are  used  for  cov- 
ering houses,  and  are  worked  into  bas- 
kets ;  and  its  boughs  are  of  service  to 
make  props  and  rafters.  The  rein-deer 
of  the  Laplander,  so  essential  to  his  sup- 
port and  subsistence,  could  not  survive 
through  the  tedious  winter,  without  the 
lichen  rangiferinus,  which  he  digs  from 
beneath  the  snow.  On  the  bleak  moun- 
tains of  the  north,  the  pine,  the  fir,  the  ce- 
dar, and  man  of  the  resinous  trees  grow, 
which  shelter  many  from  the  snows  by 
the  closeness  of  their  foliage,  and  furnish 
him  in  winter  with  torches  and  fuel  for  his 
fire-side.  The  leaves  of  those  evergreen 
trees  are  filliform,  and  thus  are  adapted  to 
reverberating  the  heat,  and  resisting  the 
violent  winds  which  beat  on  elevated  situ- 
ations* All  these  productions,  and  the 
various  trees  which  produce  cork  and 
emit  rosin,  turpentine,  pitch,  gums,  and 
balsam,  either  supply  some  constant  ne- 
cessity, obviate  some  inconvenience?  or 


Plants.  199 

contribute  to  some  use  or  gratification  of 
the  natives  of  the  soils  where  they  grow,,, 
or  of  the  inhabitants  of  distant  climate^ 


200  Animals. 


CHAP.  XL 

Of  Animals. 

WE  are  now  come  to  consider  the  last, 
the  noblest  and  the  most  beautiful  part  of 
the  creation  :  the  creatures  for  whom  this 
earth  seems  to  have  been  entirely  form- 
ed, and  for  whose  repast  or  use  the  whole 
of  its  unintelligent  productions  appear  to 
have  been  brought  forth  ;  these  are  the 
animated  tenants  of  our  globe. 

When  we  compare  animals  and  vegeta- 
bles together,  each  in  their  most  perfect 
state,  nothing  can  be  easier  than  to  dis- 
tinguish them.  The  plant  is  confined  to 
a  particular  spot,  and  exhibits  no  marks 
of  consciousness  or  intelligence  ;  the  ani- 
mal, on  the  contrary,  can  remove  at  plea- 
sure from  one  place  to  another,  is  posses- 
sed of  consciousness,  and  a  high  degree 
of  intelligence.  But  on  approaching  the 


eont 

\7pcrf 


Animals.  201 


contiguous  extremities  of  the  animal  and 
vegetable  kingdom,  these  striking  differ- 
ences gradually  disappear,  the  objects  ac- 
quire a  greater  degree  of  resemblance, 
and  at  last  approach  each  other  so  near- 
ly, that  it  is  scarcely  possible  to  decide 
whether  some  of  those  species  which  are 
situated  on  the  very  boundary,  belong  to 
the  animal  or  vegetable  kingdom.  In- 
deed we  find  the  vegetable,  animal,  and 
mineral  kingdoms  so  closely  connected, 
like  the  links  of  a  chain,  that  there  is  no 
possibility  of  finding  a  disjunction  in  any 
part,  nor  saying  with  precision  where  the 
«one  ends  and  the  other  begins,  so  nearly 
do  they  approach  each  other  in  the  ex- 
tremes of  each  class* 

The  term  animal,  in  a  general  sense, 
is  applied  to  every  thing  that  is  supposed 
to  be  alive  to  the  sensations  of  pain  and 
pleasure.  Under  the  name  of  animal, 
therefore,  are  included  men,  quadrupeds, 
ibirds,  fishes,  reptiles,  and  insects.  Ani- 
xnal  literally  means  a  living-  thing- ;  but 
plants  live.  Linnaeus  has  formed  a  cli- 
max of  the  grand  departments  of  crea- 
tion. Stones  grow  ;  vegetables  grow  and. 
live  ;  animals  grow,  live*  and  feel. 
R2 


202  Animate* 

Various  are  the  corporeal  forms,  and 
great  are  the  peculiarities  of  organization 
of  the  different  animals  which  inhabit  the 
globe ;  and  equally  various  are  their  in- 
tellectual powers;  beginning  with  man, 
who  forms  the  highest  link  in  the  chain, 
and  descending  by  an  almost  impercepti- 
ble diminution  of  mental  powers,  through 
an  innumerable  series  of  existences,  and 
ending  at  last  in  mere  animation  alone, 
with  a  seeiuing  privation  of  all  mental 
perception  whatever. 

As  an  animal,  man  is  strikingly  dis- 
tinguishable from  the  rest  of  the  crea- 
tures of  the  earth,  on  account  of  the  in- 
genuity with  which  he  eir ploys  the  pro- 
ductions of  nature  for  his  accommoda- 
tion and  comfort.  He  is  also  particular- 
ly distinguishable  by  the  originality  of 
his  ideas.  Instincts,  in  common  with 
brutes,  make  up  a  part  of  his  character; 
but  he  is  principally  the  creature  of  ex- 
perience ancl  reflection.  When  an  infant 
comes  into  the  world  it  is  the  most  help- 
less of  all  creatures  ;  no  danger  alarms 
it,  nor  can  it  make  the  smallest  effort  to 
preserve  itself.  A  tiger  may  approach 
it  without  occasioning  terror  ;  nor  would 


Animals.  203 

it,  attempt  to  screen  itself  when  the  lion's 
mouth  is  opened  to  devour  it.  The  voice 
of  the  mother  is  not  understood  for  ma- 
ny weeks  ;  and  it  is  but  by  slow  degrees 
that  it  acquires  knowledge,in  consequence 
of  the  gradual  developement  of  its  rea- 
soning faculties  ;  but  as  its  progress  is 
more  slow,  so  its  ultimate  attainments 
are  proportionally  greater  than  that  of 
other  animals.  The  chicken,  within  the 
first  eight  clays  of  its  life,  seems  to  have 
made  nearly  the  whole  mental  acquire- 
ments it  is  ever  capable  of  attaining;  but 
no  period  of  human  life  can  be  assigned 
when  the  mental  progress  of  man  is  at  a 
stand.  Man  alone  is  able  to  form  an  idea 
of  an  abstract  proposition  or  to  reason 
about  distant  occurrences.  He  alone  can 
reason  from  consequences  to  remote 
causes,  and  can  from  the  creature  trace 
an  idea  of  the  Creator.  A  sense  of  reli- 
gion, then,is  the  characteristic  peculiarity 
which  decisively  marks  a  separation  be- 
tween man  and  all  other  animals. 

But  as  the  understanding  of  man  and 
the  structure  of  his  frame  will  occupy  the 
following  chapters,  we  will  in  this  con- 
fine ourselves  to  a  view  of  the  other  parts 
o  f  a  n  i  t\i  at e  d  n  at ur e  • 


Animals. 

Animals,  like  vegetables,  differ  in  their 
sizes  and  powers,  with  respect  to  the 
places  of  their  growth.  Those  produc- 
ed in  a  dry  sunny  soil,  are  strong  and  vi- 
gorous, though  not  luxuriant :  those  again 
produced  in  a  warm  and  moist  climate 
are  luxuriant  and  tender,  and  much  lar- 
ger than  those  produced  in  other  coun- 
tries ;  as  in  the  internal  parts  of  South 
America  and  Africa,  particularly  in  the 
former  place,  where  the  earth  worm  is 
near  a  )*ard  long,  and  an  inch  thick  ;  the 
Serpents  sometimes  forty  feet  in  length ; 
the  Bats  as  large  as  Rabbits ;  Toads  big- 
ger than  Ducks  ;  :md  the  Spider  equal  in 
size  to  the  English  Sparrow.  But  in  the 
frozen  regions  of  the  north,  animals  are 
scarce  ;  and  what  few  there  are,  except 
the  .Bear,  are  not  above  half  the  size  of 
those  in  the  temperate  zone. 

Animals  are  also  found  to  vary  consid- 
erably according  to  their  food  or  climate  ; 
and  there  are  but  few  of  the  animal 
kingdom,  (and  these  are  they  that  are 
the  most  useful)  which  are  found  capa- 
ble of  attending  man  in  his  peregrina- 
tions' over  the  globe.  In  uncultivated 
nature,  the  animal  kingdom  exceeds  the 


Animate.  205 

vegetable  ;  -but,  in  a  state  of  improve- 
ment, tbe  interest  of  man  so  directs  it, 
that  the  vegetable  kingdom  should  gain 
the  ascendancy ;  for  on  a  review  of  the 
animal  and  vegetable  world,  we  find  but 
few  animals,  which  are  intrinsically  ser- 
viceable to  man  ;  while  on  the  other  hand, 
numbers  of  them  are  noxious  to  his  food, 
and  inveterate  enemies  to  his  interest. — 
But  among  the  vegetable  world,  very  few 
are  noxious  ;  and  the  greater  part  of 
them  yield  either  food,  medicine,  or  some 
other  valuable  article.  Therefore,  it  al- 
ways has,  and  will  remain  to  be,  the  in- 
terest of  man,  to  diminish  the  number  of 
animals,  and  increase  that  of  vegetables  ; 
and  in  assistance  to  his  endeavours,  pro- 
vidence has  wisely  ordered  it,  that  one 
animal  shall  subsist  on  another  ;  for  were 
they  to  live  entirely  on  vegetables,  myri- 
ads would  soon  become  extinct,  for  want 
of  support. 

The  number  of  animals,  which  are  im- 
mediately serviceable  to  man,  (exclusive 
of  the  smaller,  among  the  birds  and  fish- 
es, which  serve  for  food)  does  not  extend 
to  one  hundred  ;  while,  we  are  acquaint- 
ed with  no  less  than  twenty  thousand ; 


2O6  Animak. 

and  even  this  great  number,  compre- 
hends but  a  small  portion  of  animated  na- 
ture. Not  only  the  earth,  air,  and  sea, 
teem  with  myriads  of  living  creatures, 
but  almost  every  vegetable,  and  each  sin- 
gle leaf,  is  covered  with  an  endless  num- 
ber of  inhabitants,  whose  various  forms 
and  properties  have  afforded  matter  of 
astonishment  to  the  microscopic  obser* 
ver. 

Animals  are  nourished  by  food,  taken 
in  at  the  mouth,  digested  in  the  stomach, 
and  thence,  by  fit  vessels,  distributed 
over  the  whole  body  ;  but  of  the  process 
by  which  the  various  vegetable  produc- 
tions, which  form  the  food  of  a  large  por- 
tion of  animals,  is  converted  into  part  of 
the  animal,  we  are  totally  ignorant.  That 
this  change  does  take  place  we  know, 
but  in  what  manner  we  know  not  any 
more  than  the  animals  themselves  do, 
whose  natural  organs  perform,  unknown 
to  them,  the  functions  that  are  necessary 
for  producing  these  changes. 

The  greatest  part  of  animals  have  five 
senses,  viz.  seeing,  hearing,  smelling, 
tasting,  and  feeling.  These,  and  the  way 
of  nourishment  of  animals,  we  shall  more 


Animals,  207 

particularly  consider,  as  they  are  com* 
mon  to  man  with  beasts,  in  the  following 
chapter. 

Animals  are  generally  divided  into 
male  and  female,  and  some  are  both  male 
and  female,  and  are  called  hermaphro- 
dites, as  the  earth  worm  and  some  others* 
With  regard  to  their  mdnner  of  propa- 
gation, they  are  divided  into  oviparous? 
bringing  forth  eggs  ;  and  viviparous^ 
bringing  forth  their  young  alive. 

Linnaeus  divides  animals,  according  to 
their  internal  structures.  Some  have  the 
heart  with  two  ventricles,  and  hot,  red 
blood  : — viz.  Quadrupeds  and  Birds  ; 
others  have  the  heart  with  one  ventricle, 
and  cold,  red  blood,  viz.  Amphibia  and 
Fishes  ;  the  former  being  furnished  with 
lungs,  and  the  Fishes  with  gills.  Some 
have  the  heart  with  one  ventricle^  and 
cold,  white  serum,  viz.  Insects  and 
Worms  ;  the  former  being  furnished 
with  feelers,  and  the  latter  with  holders* 
All  quadrupeds,  which  have  teats,  are 
distinguished  by  their  teeth.  These 
form  the  following  seven  orders ;  the 
Primates  or  Principals,  which  have  four 
suiting  teeth  in  each  jaw  ;  the  Brutse  or 


208  Animals. 

Brutes,  which  have  no  cutting  teeth  ;  the 
Ferae  or  Wild  Beasts,  which  have  six  cut- 
ting teeth  in  each  jaw;  the  Glires,  or 
Dormice,  which  have  two  cutting  teeth 
both  above  and  below  ;  the  Pecora,  or 
Cattle,  which  have  no  cutting  teeth  above, 
and  six  or  eight  below  ;  the  Belluse.  or 
Beasts,  properly  so  called,  which  have  the 
fore  teeth  blunt ;  and  the  Cetse,  or  those 
of  the  Whale  kind,  which  have  cartilagi- 
nous teeth.  This  is  the  brief  outline  of 
this  celebrated  Naturalist's  arrangement, 
the  names  of  the  different  animals,  and 
their  respective  classes,  occupying  no 
less  than  two  large  octavo  volumes  ;  but 
the  natural  division  of  animated  nature,  is 
universally  allowed  to  be  the  five  follow- 
ing classes  ;  Quadrupeds,  Birds,  Fishes^ 
Insects,  and  Amphibious  Animals  ;  tho' 
it  must  be  confessed  that  this  distribution 
is  not  exactly  defined  by  nature  ;  as  there 
are  many  animals  whose  form  and  quali- 
ties render  it  difficult  to  reduce  them  to 
any  one  of  these  classes. 

I.  QvMdrupeds.  Quadrupeds  are  a  large 
and  useful  class  of  animals,  whose  gener- 
ic characters  are  these  ;  their  bodies  are 
covered  with  hair:  they  have  four  feet; 


Animals.  209 

they  are  viviparous ;  and  the  females 
suckle  their  young. 

Quadrupeds  are  the  most  important 
creatures  to  man,  and  deserve  his  atten- 
tion more  than  the  inhabitants  of  either 
the  air,  or  the  water.  They  inhabit  the 
same  soil  with  man ;  and  among  them  are; 
found  beings  possessing  a  greater  share 
of  instinct  than  the  inhabitants  of  either 
air  or  water  ;  they  breathe  through  their 
lungs,  like  the  human  species  ;  like  these 
they  are  viviparous  ;  they  have  also  warm 
red  blood  circulating  through  their  veins  ; 
and,  however  mortifying  the  reflection  to 
human  pride,  many  of  them,  both  in  their 
internal  and  external  form,  bear  a  strong 
resemblance  to  man  »  the  interior  struc- 
ture of  some  of  the  ape  kind,  so  nearly 
resembles  that  of  the  human  kind,  that 
anatomists  can  scarcely  discover  where 
the  peculiarity  exists. 

Though  the  characters  of  Quadrupeds 
are  so  obvious,  yet  as  all  the  parts  of  na- 
ture are  united  together,  to  form  one 
grand  whole  ;  there  are  several  species, 
which  seem  to  be  of  an  equivocal  na- 
ture, and  which  form  the  links,  uniting 
different  animals  together ;  as  the  Bat 
S 


2TO  Animals. 

and  Porcupine,  the  former  of  which  pos- 
sesses wings,  and  the  latter  quills,  like 
Birds  ;  the  Armadillo  is  covered  with  a 
hard  shell,  by  which  it  seems  to  partake 
of  the  nature  of  Insects,  or  Snails  ;  and 
the  Seal  and  the  Morse,  though  evidently 
of  the  quadruped  kind,  are  furnished  with 
fins,  and  reside  almost  constantly  in  the 
water. 

Quadrupeds,  like  all  other  animals,, 
are  wisely  adapted  by  Providence  to 
their  respective  situations  and  natures* 
Those  which  turn  up  the  ground  in  pur- 
suit of  their  food,  have  sharp  snouts  ; 
others,  which  require  a  keener  scent,  as 
dogs,  particularly  those  of  the  chase,  have 
long  noses,,  whereby  the  olfactory  nerves 
are  more  perfect :  while  others,  of  a  ra~ 
pncious  nature,  have  short  thick  noses, 
whereby  their  jaws  have  a  greater  mus- 
cular power,  as  those  of  the  Lion  ;  and 
all  granivorous  animals  have  a  strong 
tendinous  ligament,  extending  from  the 
head  to  the  middle  of  the  back,  to  ena- 
ble them  to  hold  down  their  heads  to 
the  ground  ;  the  fore  teeth  of  these  ani- 
mals are  also  edged,  for  the  purpose  of 
cutting  their  food ;  but  those  of  carni* 


Animals.  %'il 

vorous  animals  are  sharp,  and  serve 
rather  as  weapons  o£  defence,  In  both,, 
however,  the  surfaces  of  the  grinding 
teeth  are  unequal  and  jagged,  locking  in- 
to each  other  when  the  jaws  are  brought 
into  contact.  The  stomach  of  carnivo- 
rous animals  is  also  small  and  glandular  ; 
and  affords  such  juices  as  are  best  adap- 
ted to  digest  and  macerate  its  contents  ; 
but  those  animals  which  subsist  on  a 
vegetable  diet,  have  four  stomachs  ;  all 
which  serve  as  so  many  laboratories,  to 
prepare  the  food  for  the  nourishment  of 
the  body  ;  and,  in  general,  granivorous 
animals,  whose  food  is  easily  procured, 
have  large  capacious  stomachs,  and  ca- 
pable of  great  dilation  ;  whereas  carni- 
vorous creatures  have  the  stomach  more 
contracted,  and  the  intestines  curtailed^ 
whereby  they  are  enabled  to  subsist  for 
a  longer  time  without  food.  Strong 
large  animals,  which  are  neither  tbrmed 
for  pursuit  rior  flight,  as  the  Elephant, 
Rhinoceros,  Sea- Horse,  &c.  have  thick 
massy  legs,  to  support  their  unweildy  bo- 
dies. While  Deers,  Hares,  and  other 
creatures,  whose  safety  depends  on  flight, 
and  who  are  beset  by  numberless  ene- 


212  Animals 

mies,  have  long,  slender,  hut  muscular 
legs.  Those  formed  for  a  life  of  rapa- 
city have  their  feet  armed  with  sharp 
claws,  which  in  some  species  are  retrac- 
tile, as  those  of  the  Cat ;  and,  on  the 
contrary,  peaceful  animals  are  generally 
furnished  with  hoofs,  which  often  serve 
sis  weapons  of  defence  ;  and  the  feet  of 
those  which  subsist  on  fish,  have  mem- 
branes betwen  the  toes,  the  better  to 
enable  them  to  pursue  their  prey  in  the 
•watery  element. 

The  larger  species  of  Quadrupeds  are, 
in  general,  the  most  harmless  and  inof- 
fensive ;  and,  as  if  sensible  of  their  own 
innocence,  they  possess  the  most  courage ; 
while  the  more  rapacious  animals  are  in- 
ferior to  those  in  size,  and  also  in  cour- 
age ;  and,  except  the  Dog,  there  is  no 
carnivorous  quadruped,  that  will  volun- 
tarily attack  another  animal,  when  the 
odds  is  against  him.  Thus  nature  has 
furnished  the  most  inoffensive  animals 
with  superior  size  and  strength  ;  and  op- 
posed to  them  the  carnivorous  kinds, 
which  possess  more  cunning  and  agility, 
whereby  an  equilibrium  is  preseved  be- 
t  v/een  the  numbers  of  the  different  kinds. 


Animals* 

The  carnivorous  animals  are,  in  gen- 
eral, confined  to  their  retreats  during  the 
day,  and  commit  their  depredations  by 
night ;  when  the  forest  resounds  with  the 
tremendous  roar  of  the  Lion,  the  hide- 
ous yell  of  the  Tiger  ;  the  barking  of  the 
Jackal;  the  dismal  cry  of  the  Hyaena; 
and  the  hissing  of  the  Serpent.  Most 
of  these  kinds  of  animals  take  their  prey 
by  surprise  from  some  ambush,  where 
they  lay  in  wait,  more  than  by  a  regular- 
pursuit.  There  are  some,  however,  which 
pursue  in  companies,  mutually  encoura- 
ging each  other  by  their  cries,  as  the  Jack- 
al, Syagush, Wolf,  and  Dog.  Carnivorous 
animals  will  sometimes  devour  the  lesser 
rapacious  species  ;  but  they  generally  pre- 
fer the  flesh  of  granivorous  creatures,  and 
commit  their  devastations  among  the 
peaceful  domestic  flocks  and  herds.— The 
most  defenceless  creatures  have  different 
methods  of  providing  for  their  safety* 
Some  find  protection  in  the  holes  they 
form  in  the  earth  ;  others  are  enabled  to 
escape  their  pursuers  by  flight ;  others 
again  unite  for  their  mutual  defence,  and 
gain,  by  numbers,  what  they  want  indivi- 
dually in  strength  ;  and,  lastly,  other? 
S2 


Animals. 

avoid  their  enemies,  by  placing  some  ot 
their  own  company  as  centinels,  to  warn 
them  of  the  first  approach  of  danger  ;  a 
duty  in  which  they  are  seldom  negligent, 
and  for  the  neglect  of  which  they  are  in- 
variably punished  by  the  rest. 

II.  Birds. — Birds,  next  to  quadrupeds 
seem  to  demand  our  attention.  The 
generic  characters  of  this  class  of  animals 
are  these  ;  the  body  is  covered  with  fea- 
thers, and  furnished  with  two  legs,  two 
•wings,  and  a  hard  horny  bill ;  and  the  fe- 
males are  oviparous. 

Birds  are  infinitely  more  numerous  in 
their  different  kinds  than  quadrupeds  9 
but  still  less  so  than  Fishes.  They  seem 
designed  by  providence  for  a  solitary  life; 
and  though  inferior  to  the  brute  creation 
in  the  powers  of  attack  and  defence,  they 
possess  a  greater  faculty  of  escape;  and  the 
greater  part  of  them  immediately  elude 
their  enemies  of  the  quadruped  and  rep- 
tile nature,  by  an  aerial  escape  ;  for  which 
all  parts  of  their  bodies  seem  admirably 
adapted  ;  the  external  form  of  the  body 
being  sharp  before  ;  swelling  gradually, 
and  terminating  in  a  1  *ge  spreading  tail, 
which  renders  it  buoyant,  while  the  fore 
part  cleaves  the  air- 


Animals. 

The  clothing  of  these  animals  is  exactly 
suited  to  their  manner  of  life.  The  feath- 
ers all  tend  backwards,  and  neatly  and 
closely  fold  over  each  other,  which  answer 
the  triple  purposes  of  warmth,  speed  and 
security.  Those  placed  next  the  skin  are 
furnished  with  a  warm  soft  down  ;  while 
the  exterior  ones  are  arrayed  with  double 
beards,  longer  at  one  end  than  the  other, 
and  which  consist  of  thin  little  laminae, 
disposed  in  regular  lines,  and  perfectly 
even  at  their  edges.  The  shaft  of  each 
feather  is  formed  of  a  thin  hollSw  tube, 
•which  answers  the  purposes  of  strength 
and  lightness  ;  the  upper  part  being  filled 
with  a  soft  pith,  to  afford  nourishment 
to  the  beards.  They  are  so  placed,  that 
the  largest  and  strongest,  or  those  of  the 
wings  and  tail,  have  the  greatest  share  of 
duty  to  perform  in  flight.  The  upper 
external  side  of  each  single  filament,  in 
the  beard  of  the  feather,  is  furnished  with 
hairs  on  its  edges,  which  lock  into  those 
of  the  next  filament,  and  thus  form  an  en- 
tire, but  light,  smooth  surface.  Birds  are 
also  furnished  with  certain  glands  upon 
their  rumps,  which  contain  a  quantity  of 
oilj  which  they  press  out  w ith  their  beaka*, 


Animals* 

and  rub  over  their  feathers;  in  order  to 
smooth  them,  and  enable  them  to  turn  off 
the  water.  Aquatic  Birds,  as  the  Duck, 
Goose,  &c.  have  a  greater  quantity  of  this 
oil;  but  those  who  live  principally  under 
cover,  and  seldom  expand  their  wings, 
have  a  less  proportion  of  it ;  as  the  com- 
mon Hen,  whose  feathers  are  impervious 
to  every  shower  of  rain. 

Birds  possess  a  perfection  of  sight  far 
superior  to  that  of  either  man  or  brute, 
which  is  necessary  for  their  safety  and 
support?  Were  it  less  perfect,  Birds  of 
rapid  flight  would  strike  against  every  ob- 
ject in  their  way ;  and  be  unable  to  disco- 
ver their  proper  food  at  a  distance.  The 
Kite  darts  on  its  prey,  from  the  greatest 
heights  to  which  it  ascends;  and  the  Hawk 
will  discover  a  Lark,  at  a  distance  too 
great  for  human  perception. 

Aquatic  Birds  have  webbed  feet,  or 
membranes  between  their  toes,  to  assist 
them  in  swimming;  other  Birds  have  their 
toes  disjoined,  the  better  to  enable  them 
to  catch  their  prey,  or  cling  to  the  branch- 
es of  trees.  Birds,  with  long  legs,  have 
also  long  necks,  to  enable  them  to  pick  up 
their  food ;  but  some  Aquatic  Birds,  as 


Animals-.  217 

the  Swan  and  Goose,  have  long  necks  and 
short  legs. 

Birds  are  destitute  of  urinary  bladders 
yet  they  have  large  kidneys  and  ureters, 
by  which  the  secretion  of  urine  is  perfor- 
med, and  then  carried  away  with  the  oth- 
er excrements,  in  one  common  canal ;  by 
which  means  they  are  less  obnoxious  to 
diseases  than  quadrupeds,  who  drink  much 
and  have  a  separate  passage  for  the  ejec- 
tion of  the  fluid  excrement. 

The  greater  number  of  Birds  pair  at  the 
approach  of  spring  ;  and  the  compact  en- 
tered into  is  inviolably  observed,  for  that 
season  at  least;  but  some  species  enter 
into  this  connection  for  years,  and  even 
for  life. 

All  Birds  are  oviparous,  and  the  Hens 
of  some  species  will  lay  eggs  though  they 
be  not  accompanied  by  the  Male  ;  as  the 
common  domestic  Hen  ;  but  eggs  of  this 
kind  are  always  sterile,  never  producing  a 
live  ani  mal.  Every  bird  builds  its  nest  in 
such  a  manner,  and  with  such  materials, 
as  best  to  answer  its  own  purpose  and  sit- 
uation ;  thus  the  Wren,  which  lays  a  great 
number  of  eggs,  requires  a  very  warm 
yies t  '9  as  her  body  is  not  sufficiently  large  ta 


218  Animals. 

cover  the  whole  of  thrm ;  but  the  Crow  and 
Eagle  are  less  solicitous  in  the  warmth  of 
their  nest,  as  the  small  number  of  eggs 
they  lay,  and  largeness  and  heat  of  their 
bodies,  afford  the  eggs  sufficient  warmth. 
The  same  Bird  also,  when  in  a  cold  cli- 
mate, lines  its  nest  with  more  care  and 
warmer  materials  than  in  a  warmer  cli- 
mate. The  male  likewise  of  most  birds, 
during  the  season  of  incubation,  supplies 
th'j  place  of  the  female,  in  her  absence 
from  the  eggs  ;  and  supplies  her  with 
food  during  the  time  of  her  sitting. 

Those  birds  which  are  hatched  early 
in  the  season,  always  prove  more  vigo- 
rous and  strong,  than  such  as  have  been 
delayed  till  the  middle  of  summer.  The 
number  of  eggs,  which  a  bird  will  lay, 
is  not  exactly  ascertained  ;  but  it  is  well 
known,  that  a  female  Bird,  which  would 
have  lain  but  two  or  three  eggs  at  most, 
will,  on  her  eggs  being  removed,  lay  above 
ten  or  a  dozen.  A  common  Hen,  if  pro- 
perly fed,  will  produce  above  a  hundred 
eggs,  from  the  beginning  of  spring  to  the 
end  of  Autumn.  Nature  has  wisely  or- 
dered it,  that  the  smallest  and  weakest 
birds ;  and  in  general,  all  those  which  are 


Animals,,  219 

most  serviceable  to  man,  are  the  most 
prolific  :  while  the  strong  and  rapacious 
kinds  are  marked  with  sterility. 

Birds  are  in  all  countries,  longer  lived 
than  the  brute  creation  ;  the  Linnet  will 
often  live  fourteen  or  fifteen  years  ;  the 
Bullfinch  tw.enty  ;  the  Goose  fourscore  ; 
while  Swans,  Eagles,  and  some  others, 
have  been  known  to  live  two,  or  even  three 
hundred  years. 

The  number  of  species  of  Birds,  which 
mankind  has  rendered  domestic,  are  but 
few,  as  the  Peacock,  Turkey,  common 
Hen,  Guinea-Hen,  Pigeon,  Swan,  Goose, 
Duck,  and  Guinea-Duck,  being  only  nine, 
while  the  number  of  all  the  species  known 
exceed  fifteen  hundred. 

III.  Amphibious  animals  are  all  those 
who  are  capable  of  living  either  on  land 
or  in  the  water.  They  are  furnished  with 
lungs  and  air  bladders,  adequate  to  this 
purpose.  Such  are  the  Frog,  Castor^ 
Otter,  Tortoise,  Sea-Galf,  Alligator,  &c* 

Numbers  of  insects,  particularly  of  the 
Fly  kind,  appear  to  be  amphibious ;  Gnats 
always  drop  their  eggs  in  water,  where 
the  young  are  hatched,  and  live  after  the 
manner  of  fishes  ;  till  at  length  they  un~ 


£20  Animals. 

dergo  a  metamorphosis,  take  wing,  quit 
their  natural  element,  and  become  inhabit- 
ants  of  the  air. 

IV.  Fishes. — Fishes  are  a  class  of  crea- 
tures that  appear,  both  in  structure  and 
sagacity  quite  inferior  to  other  animals  ; 
though  capable  of  enduring  famine  an 
amazing  length  of  time,  they  appear 
most  voracious  creatures  ;  a  ceaseless 
desire  for  food  seems  the  ruling  impulse 
of  their  actions  ;  and  their  life  one  con- 
tinued scene  of  violence  or  evasion. 

Most  fishes  present  the  same  external 
form  ;  sharp  at  both  ends,  and  bulky  in 
the  middle  ;  which  shape  is  most  conve- 
nient for  their  passage  through  the  wa- 
tery element.  Mankind  have  imitated 
this  form,  in  the  construction  of  their 
marine  vessels  ;  but  the  progress  of  such 
machines  is  far  inferior  to  that  of  fishes  ; 
any  of  which,  will,  with  ease,  outstrip  a 
ship  in  full  sail  ;  play  around  it,  loiter 
behind,  and  overtake  it. 

The  instruments  of  motion  in  these 
animals  are  the  fins  ;  of  which  the  gener- 
al complement  is  two  pair,  and  three  sin* 
gle  fins  ;  though  some  fish  possess  more, 
and  many  less  than  this  number.  The 


Animals.  221 

pectoral  fins,  are  placed  at  some  distance 
behind  the  opening  of  the  gills  ;  and  are 
generally  strong  and  large  ;  answering 
the  same  purpose,  to  a  fish,  as  wings  do 
to  a  bird  in  the  air ;  namely,  pushing 
the  body  forward,  like  the  oars  to  a  boat. 
They  also  serve  to  balance  the  body  of 
the  fish,  and  prevent  the  head  from  sink- 
ing, which  it  would  otherwise  do.  The 
ventral  fins  are  placed  under  the  belly, 
towards  the  lower  part  of  the  body ; 
these  are  always  extended  flat  on  the 
water,  in  all  situations ;  and  serve  to 
raise  or  depress  the  body  of  the  animal, 
rather  than  assist  his  progression.  The 
dorsal  fin,  is  situated  along  the  ridge  of 
the  back  ;  and  serves  to  keep  the  fish  in 
equilibrium,  and  also  assists  it  in  its  velo- 
city. This  fin  is  very  large,  in  all  the 
flat  fish  ;  the  pectoral  fins  of  which  are 
proportionally  less.  The  anal  fin,  ex- 
tends from  the  anus  to  the  tail,  and  serves 
to  keep  the  body  of  the  animal  upright, 
or  in  a  vertical  direction.  In  some  fish- 
es, as  before  observed,  the  tail  is  hori- 
zontal, and  in  others  perpendicular. — - 
Thus  equipped,  these  animals  have  the 
xiiost  rapid  motions  ;  and  perform  voy- 
T 


222  Animals. 

^ges,  of  upwards  a  thousand  leagues  is 
one  season. 

Fish  are  also  furnished  with  a  slimy 
glutinous  matter,  which  overspreads  the 
whole  body,  and  defends  them  from  the 
corosslve  quality  of  the  water.  Beneath 
this  matter,  some  have  a  strong  covering 
of  scaks,  which,  like  a  coat  of  armour, 
protects  the  body  from  injuries.  Be- 
neath which,  again,  there  is  an  oily  sub- 
stance, which  supplies  the  animal  with 
the  necessary  warmth  and  vigour. 

Fishes  possess  most  of  the  senses  in 
an  inferior  degree  to  land  animals. — • 
Their  sense  oi  smelling,  (though  furnish- 
ed with  nostrils)  is  less  perfect,  than  in 
the  other  parts  of  animated  nature, 
as  must  be  evident  from  the  nature  of  the 
fluid  they  inhabit  ;  this  sense  in  them 
can  only  act,  from  the  action  of  the  fluid, 
tinctured  with  the  odour  of  the  object^ 
upon  the  olfactory  nerves  within,  in  the 
same  manner  as  the  palates  of  other  an- 
imals discover  tastes.  Their  sense  of 
taste  must  also  be  very  imperfect  ;  their 
palate  being  of  a  hard  bony  nature ; 
•  whereas,  in  quadrupeds  who  possess 
this  sense  in  an  exquisite  degree,  this 


Animals.  223 

organ  is  very  soft  and  pliant.  From 
this  indiscrimination,  fish  will  frequent- 
ly swallow  the  plummet,  as  well  as  the 
bait.  Their  sense  of  hearing  is  still 
more  defective,  if  they  possess  this  facul- 
ty at  all,  as  is  evident  from  the  frequent 
experiments  which  have  been  made. 
No  fish,  except  the  whale  kind,  have  the 
least  appearance,  on  dissection,  of  any 
auditory  organs.  Their  sense  of  sight^ 
is  however  somewhat  more  perfect, 
though  inferior  to  that  of  most  other  an- 
imals. They  are  totally  destitute  of 
eyelids ;  the  eyes  being  covered  with 
the  same  skin  that  overspreads  the  rest 
of  the  body. 

The  period  to  which  fishes  live,  is  ve- 
ry little  known,  though  it  is  generally 
believed  they  attain  to  a  considerable 
age  ;  some  of  the  least  exceed  in  their 
age  that  of  a  man.  The  method  of  dis- 
covering their  ages,  is  either  by  examin- 
ing the  transverse  coverings  of  their 
scales,  by  means  of  a  microscope  ;  or  by 
the  transverse  section  of  the  back  bone. 
Buffon  found  a  carp  which  by  the  former 
method  of  computation  appeared  to  be 
a  hundred  years  old,  allowing  one  year 


224-  Animals* 

for  every  covering  of  the  scales  ;  the 
Skate,  and  Ray,  like  other  fish  \vhich 
have  no  scales,  have  their  ages  discover- 
ed, by  seperating  the  joints  of  the  back 
bone,  and  then  examining  the  number  of 
rings  which  the  surface  exhibited  where 
it  vvas  joined,  allowing  one  year  for  each 
ring.  Little  can  be  said  in  favour  of  the 
certainty  of  either  of  these  methods  ; 
they  however,  though  not  infallible  cri- 
terions,  enable  us  to  make  a  near  approx- 
imation to  the  truth. 

The  greatest  singularity  in  fishes,  is 
their  amazing  fecundity.  Some  are  vi- 
viparous, and  others  oviparous  ;  the  lat- 
ter produce  their  young,  or  rather  their 
eggs,  in  far  greater  abundance  than  the 
former ;  but  at  the  same  time  they  are 
more  subject  to  become  the  prey  of  oth- 
er fish,  and  even  of  their  own  species, 
not  excepting  the  parent  itself  which  ex- 
cluded them,  while  they  continue  in 
their  egg  state  ;  consequently  but  very 
few  of  these  eggs  produce  live  animals, 
though  produced  in  such  considerable 
numbers.  A  single  Cod  will  produce 
above  nine  million  of  eggs  in  one  sea- 
son ;  and  many  other  fish  have  as  pro- 
portionable an  increase* 


, 

the^ 


Animals.  225 


V.  Insects. — Insects  and    animals    of 
e  worm  kind,  seem  to  form  the  lowest 
order  among  the  various  tribes  of  living 
creatures  which  inhabit  our  globe.     The 
distinguishing  characters  of  insects  are, 
that  their  bodies  are  covered  with  'i 
of  bony  substance  instead  of  &1  ; 
their  heads  furnished  with 
horns.     An  insect,  may  moi •;.- 
ly  be  defined  a  small  animal  w, 
blood,  (this  matter  being,  white  a 
bones,   or   cartilages  ;    furnished 
trunk,   or    else    a   mouth,    which    d 
length  ways,  contrary  to  the  natural  or- 
der ;  the  eyes  destitute  of  covering  ;  and 
lungs  opening  on  the  sides  of  the  body. 
This    definition    will    comprehend    the 
whole   class  of  insects  of  every  descrip- 
tion.   This  class  of  beings  is  so  numerous, 
and  so  various,  as  to   exceed  the   most 
accurate  and  unwearied  observations. — 
To  give  the  different  species  of  only  flies 
and  moths,  would  be  a  fruitless  attempt ; 
but  to  give  the  history  of  every  species 
of  insect  would  be  utterly  impracticable  ; 
so  varied  are  they  in  their  forms,  sizes, 
habitudes,  methods  of  propagation,  and 
manners  and  duration  of  life.     A  gener* 
T2 


226  Animals. 

al  division  of  them,  however,  according 
to  their  most  apparent  external  differ- 
ences of  form,  may  be  attempted. 

The  first  class  of  these  beings,  which 
present  themselves  to  our  observation, 
appear  to  be  those  which  are  destitute  of 
\vings,  and  are  seen  crawling  about  on 
every  plant  and  spot  of  earth.  Some  of 
these  never  acquire  wings,  but  continue 
in  this  reptile  state  during  their  whole 
lives.  These  are  all  oviparous,  except 
the  Flea  and  the  Wood-Louse  ;  and  pro- 
perly constitute  the  first  division  of  in- 
sects. Others  which  hereafter  become 
winged  insects,  belonging  to  the  following 
divisions. 

The  second  grand  division  of  insects, 
are  those  furnished  with  wings  ;  but 
which,  when  first  produced  from  the 
egg,  appear  like  reptiles,  and  have  their 
wings  so  cased  up,  as  to  be  quite  con- 
cealed ;  but  when  these  cases  break,  the 
wings  expand,  and  the  animal  acquires 
Its  perfect  form  and  beauty.  Of  this 
nature  are  the  Dragon  Fly,  the  Grass- 
hopper, and  the  Ear- wig. 

The  third  order  of  insects,  are  those 
of  the  Moth,  and  the  Butterfly  kind. 


Animals.  227 

which  have  all  four  wings  each,  covered 
with  a  mealy  substance  of  various  colours, 
which  easily  rubs  off;  and  when  examin- 
ed by  the  microscope,  appears  to  be  ele- 
gant scales.  These  insects  have  a  pecu- 
liar method  of  propagation  ;  they  are  ovi- 
parous :  and  when  first  hatched  from  the 
egg,  are  perfect  caterpillars,  which  often 
shed  their  skins  ;  and  after  having  dives- 
ted themselves  of  their  skins  for  the  last 
time,  assume  new  coverings  called  chrys- 
alides, in  which  state  they  continue  till 
they  come  forth  in  their  perfect  winged 
forms. 

The  fourth  division  include  those  wing- 
ed insects  which  originate  from  Worms, 
and  not  from  Caterpillars  like  the  for- 
mer, though  they  undergo  similar  trans- 
formations. Some  of  these  are  furnished 
with  two,  and  others  with  four  wings 
each.  The  wings  of  animals  of  this  class 
differ  from  those  of  the  Moth  and  But- 
terfly kind,  in  being  destitute  of  those 
scales  with  which  these  are  furnished. 
This  class  includes  all  the  numerous 
class  of  Flies,  Gnats,  Beetles,  &c. 

The  fifth  and  last  class  of  insects,  con- 
tain those  which  naturalists  have  termed 


228  Anzmak. 

Zoophytes  ;  and  are  distinguished  by 
their  peculiar  mode  of  propagation,  so 
different  from  the  ordinary  course  of  na- 
ture. They  may  be  multiplied  by  dissec- 
tion ;  a'jci  some  of  thorn,  though  cut  in  a 
hundred  pieces,  will  still  retain  the  vital 
principle  in  each  separate  part ;  each  part 
shortly  becoming  a  perfect  animal ;  which 
ni  ;y  iv^aiu  be  increased  in  the  same  man- 
ner. To  this  class  belong  the  Polypus, 
the  Earth-worm,  and  all  the  varieties  of 
the  Sea  Nettlt. 

Insects  are  furnished  with  all  the  ne- 
cessary appendages  proper  to  each,  for 
the  purposes  of  defence,  of  flight,  or  pro- 
viding for  their  own  subsistence.  The 
different  parts  of  their  bodies,  are  also 
constructed  with  admirable  skill.  The 
eye,  for  instance,  is  differently  formed 
from  that  of  any  other  creature  :  it  is  ex- 
ternally rigid,  whereby  it  is  not  obnoxious 
to  many  injuries  ;  the  cornea  is  divided 
in  every  part  into  lenticular  facets,  which, 
viewed  by  the  microscope,  appear  like  a 
beautiful  piece  of  lattice-work,  each  open- 
ing reflecting  the  rays  of  light  so,  that 
when  looked  through,  the  object  appears 
inverted,  and  thereby  supplies  the  place  of 


Artimals.  229 

crystalline  humour,  of  which  insects  are 
intirely  destitute.  Larger  animals  are 
obliged  to  turn  their  eyes  towards  the  ob- 
ject they  wish  to  behold,but  many  insects, 
us  flies,  have  their  eyes  so  constructed  as 
to  admit  the  view  of  every  neighbouring 
object  at  once.  The  numbur  of  eyes  are 
very  different  in  different  insects  ;  some 
have  only  one  ;  others  have  two  ;  spiders 
have  generally  eight;  and  flies  have  as 
many  as  there  are  perforations  in  the  cor- 
nea, which  are  very  numerous.  Most  in- 
sects are  furnished  with  two  antennas,  or 
feelers,  which  serve  to  keep  their  eyes 
clean.  Amphibious  insects  have  their  feet 
formed  of  flat  joints  ;  and  gristles  placed 
on  each  side  of  the  extremity  of  the  limb, 
which  supply  the  place  of  oars,  as  in  the 
Water- Beetles.  Insects  formed  for  leap- 
ing, as  the  Cricket  and  Grasshopper, 
have  strong,  brawny,  muscular  legs;  while 
those  who  use  their  claws  in  perforating 
the  earth,  have  these  members  admirably 
adapted  for  this  purpose. 

Insects  and  reptiles,  though  seemingly 
the  most  insignificant  of  animated  beings 
have  an  important  part  assigned  them  to 
perform  in  this  universe.  Though  the 


230  Animals. 

duration  of  their  life  be  but  as  a  moment 
and  their  strength,  when  compared  with 
that  of  the  larger  animals,  as  nothing  yet 
their  power  is  often  irresistible.  The 
strongest  animal  which  treads  the  earth 
is  frequently  driven  to  madness  by  the 
endless  irritation  these  insignificant  beings 
produce  ;  the  sun  himself  is  deprived  of 
his  light  by  the  shading  of  their  wings, 
and  every  leaf  that  can  give  support  to  an- 
imal life  is  often  swept,  at  once,  away  by 
their  devouring  jaws  ;  neither  has  the  in- 
genuity of  man,  which  subdues  the  stron- 
gest, and  reclaims  the  most  ferocious  an- 
imals, enabled  him  to  devise  the  means 
of  defending  himself  from  the  devastation 
of  these  active  invaders  of  his  rights. 
His  very  existence  itself,  on  many  occa- 
sions, depends  upon  his  speedily  with- 
drawing beyond  the  sphere  of  their  ac- 
tive incursions. 

If  their  power  be  thus  irresistible,  their 
utility  is  not  perhaps  less  conspicuous  on 
this  globe.  Man  has  ever  been  able,  on 
some  occasions,  to  make  them  become 
subservient  to  his  will.  The  bee  collects 
honey  for  his  use  ;  the  moth,  under  his 
influence,  affords  him  silk  ;  the  cantharis 


Animals.  231 

an  active  drug;  the  cochineal  insect  the 
most  brilliant  of  his  dyes.  Even  where 
they  are  totally  beyond  his  control  they 
minister  indirectly  to  his  wants.  Under 
the  form  of  eggs,  maggots,  grubs,  cater- 
pillars, aurelice,  and  flies,  they  furnish  food 
to  innumerable  creatures,  who  augment 
his  comforts  in  a  thousand  ways.  But  it  is 
as  the  scavengers  of  this  universe  that 
these  puny  beings  become  chiefly  saluta- 
ry to  man,  and  all  animated  nature.  With-* 
out  their  unceasing  aid  in  this  respect, 
the  air  would  become  quickly  tainted  with 
the  most  noxious  effluvia,  which  would 
soon  put  an  end  to  animal  existence.  To 
obviate  this,the  beneficentCreator  hath  de- 
creed, that  a  numerous  department  of  this 
class  of  beings,  while  in  their  reptile  state, 
shall  be  unceasingly  employed  in  searching 
for  and  devouring  every  thing  that  has 
once  lived,  and  is  now  tending  to  decay.— 
Under  this  state  of  degradation  these 
creatures  are  doomed  to  labour  for  a  time 
•with  unceasing  assiduity  :  and  that  no- 
thing might  divert  their  attention  from 
this  important  business,  even  for  one 
moment,  the  distinctions  of  sex  are  with- 
held from  them  while  in  this  state  ;  nor 


232  Animals. 

does  it  seem  that  these  have  a  single  per- 
ceptive faculty,  unless  it  be  that  of  stri- 
ving to  preserve  their  existence,  and  al- 
lay their  insatiable  appetite  for  food.—- 
Having,  at  length,  however,  with  the 
most  patient  assiduity,  performed  the 
mental  task  that  was  assigned  them,  they 
are  then  called,  by  the  bounty  of  the  Cre- 
ator, into  another  and  superior  state  of 
existence,  in  which  thev  are  destined  to 
perform  a  part  the  most  opposite  which 
can  be  conceived  to  that  they  formerly  ac- 
ted. The  unsightly  grub,  after  a  tempo- 
rary death,  awakens  into  new€  life  ;  and 
deserting  the  clod  it  lately  inhabited,  and 
nauseating  its  former  food,  sports  in  the 
sun-beam,  and  sips  the  balmy  dew  ;  nor 
does  the  butterfly,  now  arrayed  in  the  most 
gorgeous  attire,  seem  to  claim  the  most 
distant  alliance  with  the  ugly  caterpillar 
from  whence  it  sprang.  The  attraction 
of  sex  seems  to  form  the  chief  business  of 
this  period  of  life  ;  food  is  neglected  as  if 
unnecessary,  and  its  life  is  devoted  to  am- 
orous dalliance  alone.  Having  soon  pro- 
vided a  numerous  progency  of  voracious 
labourers,  it  leaves  this  transitory  scene, 
to  make  room  for  those  who  are  destined 


Animals*  233 

to   supply   its   important'    place   in  the 
universe. 

The  changes  and  transformations  of  in- 
sects  are  first  from  the  ovum  (egg)  into 
the  larva  (caterpillar  or  maggot;)  then  in- 
to the  pupa  (chrysalis)  and  lastly  into  the 
imago  (fly.)  Pupa  is  a  name  derived  from, 
the  resemblance  of  the  insect  in  this  state 
to  an  infant  in  swaddling  clothes  ;  and  the 
term  is  now  used  in  preference  tochrysalis. 
The  period  of  existence  in  each  of  these 
states  varies  greatly  in  different  species 
of  insects ;  but  in  general  they  continue 
much  longer  in  the  reptile  state  than  in 
that  of  the  fly.  The  species  of  fly  called 
ichneumon  remains  in  the  water  as  a  kind 
of  worm  for  the  space  of  about  two  years; 
in  its  fly  state  it  seldom  continues  more 
than  one  day.  The  ephemeron  is  nearly 
the  same  ;  and  the  grub  of  the  cockchaffer 
remains  vmder  ground  for  about  two  years 
also  ;  in  its  fly  state  it  in  general  exists 
only  about  two  months. 


2*34  ffuman  Frame. 

CHAP.  XII. 

Of  the  Human  Frame. 

MAN  is  placed  at  the  head  of  the 
animal  creation.  Animated  and  enlight- 
ened by  a  ray  from  the  Divinity,  he  sur- 
passes in  dignity  every  material  being- 
He  was  made  after  all  other  creatures^ 
not  only  as  the  most  perfect,  but  as  the 
surperintendent  and  master  of  all  things  ; 
created  u  to  rule  over  the  fish  in  the  sea, 
and  over  the  fowl  of  the  air,  and  over 
cattle,  and  over  the  earth,  and  over  every 
creeping  thing*" 

The  body  of  a  well-shaped  man  ought  to 
be  square,  the  muscles  ought  to  be  strong- 
ly marked,  the  contour  of  the  mejnb 
boldly  delineated,  and  the  features  c£ 
the  face  well  defined.  In  women,  all  the 
parts  are  more  rounded  and  softer,  the 
features  are  more  delicate,  and  the  com- 
plexion brighter.  To  man  belong  strength 
and  majesty ;  gracefulness  and  beauty 


Hum  an  Fram  e.  235 

the  portion  of  the  other  sex.— Every 
thing  in  both  sexes  points  them  out  as 
sovereigns  of  the  earth  ;  even  the  exter- 
nal appearance  of  man  declares  his  su- 
periority to  other  living  creatures.  His 
head  tends  towards  the  heavens,  and  in 
his  august  countenance  beams  the  sacred 
ray  of  sapient  reason.  He  alone  sheds 
the  tears  which  arise  from  emotions  of 
sensibility,  unknown  to  animals  ;  and  he 
alone  expresses  the  gladness  of  his  soul 
by  laughter.  His  erect  posture  and  ma- 
jestic deportment  announce  his  dignity 
and  superiority.  He  touches  the  earth 
only  with  the  extremity  of  his  body  ; 
his  arms  and  hands,  formed  for  nobler 
ends  than  the  correspondent  organs  of 
quadrupeds,  execute  the  purposes  oi  his 
mind,  and  bring  every  thing  within  his 
reach,  which  can  minister  to  his  wants 
and  his  pleasures.  By  his  eyes,  which 
reflect  the  intelligence  of  thought,  and 
the  ardour  of  sentiment,  and  which  are 
peculiarly  the  organs  of  the  soul,  are  ex- 
pressed the  soft  and  tender,  as  well  as  the 
violent  and  tumultuous  passions.  They 
are  turned,  not  towards  the  heavens,  but 
to  the  horizon,  so  that  he  may  behold  at 


236  Human  Frame. 

once  the  sky  which  illuminates,  and  the 
earth  which  supports  him.  Their  reach 
extends  to  the  nearest  and  the  most  dis- 
tant objects,  and  glances  from  the  grains 
of  sand  at  his  feet,  to  the  star  which  shines 
over  his  head  at  an  immeasurable  dis- 
tance. 

'The  human  body  consists  of  solid  and 
fluid  parts,  which  in  general  are  called 
the  solids  and  fluids,  or  humours  of  the 
body.  The  solid  parts  are  bones,  cartil- 
ages, ligaments,  muscles,  tendons,  mem- 
branes, nerves,  arteries,  veins,  ducts,  or 
fine  tubular  vessels  of  various  sorts.  Of 
these  simple  solids  the  more  compound 
organs  of  life  consist,  viz.  the  brain  and 
cerebellum  ;  the  lungs,  the  stomach,  the 
liver,  the  spleen,  the  pancreas,  the  kid- 
neys, the  glands,  the  intestines,  together 
with  the  organs  of  sense,  viz.  the  eyes> 
the  ears,  the  nose,  and  the  tongue. 

The  fluid  parts  of  the  human  body  are 
chyle,  blood,  saliva  or  spittle,  bile,  milk, 
lympha,  the  semen,  the  pancreatic  juice ', 
urine,  phlegm,  serum,  and  the  aqueous 
humour  of  the  eyes. 

Anatomists  have  employed  much  pains 
in  the  study  of  the  material  part  of  man. 


Human  If  ram  c,  237 

have  assigned  to  each  of  the  above 
parts  their  appropriate  use  in  the  econo- 
my of  his  frame,  but  none,  perhaps  have 
given  so  comprehensive  and  eloquent  a 
description  of  the  structure  of  man  as 
the  late  Dr.  Hunter.  u  In  order"  says 
this  celebrated  anatomist,  "  to  acquire 
a  satisfactory  general  idea  of  this  subject, 
let  us,  in  imagination,  make  a  man ;  in 
other  words,  let  us  construct  a  fabric  fit 
for  the  residence  of  an  intelligent  soul. 
This  soul  is  to  hold  a  correspondence 
with  all  material  beings  around  her  ;  and, 
to  that  end,  she  must  be  supplied  with 
organs  fitted  to  receive  the  different  kinds 
of  impressions  which  they  will  make* 
In  fact,  therefore,  we  see  that  she  is  pro- 
vided with  the  organs  of  sense,  as  we 
call  them  :  the  eye  is  adapted  to  light ; 
the  ear  to  sound  ;  the  nose  to  smell ;  the 
moutJi  to  taste  ;  and  the  skin  to  touch- 
Farther,  she  must  be  furnished  with  or- 
gans of  communication  between  herself 
in  the  brain  and  those  organs,  to  give 
her  information  of  all  the  impressions 
that  are  made  on  them  ;  and  she  must 
have  organs  between  herself  in  the  brain 
.\rA  r  very -other  part  of  the  body  fitted 
U2 


238  Human  Frame. 

to  convey  her  commands  and  influence 
over  the  whole.  For  these  purposes,  the 
nerves  are  actually  given.  They  are 
chords  which  rise  from  the  brain,  the 
immediate  residence  of  the  mind,  and 
disperse  themselves  in  branches  through 
all  parts  of  the  body.  They  are  intended 
to  be  occasional  monitors  agninst  all  such 
impressions  as  might  endanger  the  well- 
being  of  the  whole,  or  of  any  particular 
part ;  and  this  vindicates  the  Creator  of 
all  things  in  having  actually  subjected  us 
to  those  many  disagreeable  and  painful 
sensations  which  we  are  exposed  to  form 
a  thousand  accidents  in  life.  Moreover, 
the  mind,  in  this  corporeal  system,  must 
be  endued  with  the  power  of  moving 
from  place  to  place,  that  she  may  have 
intercourse  with  a  variety  of  objects  ;  that 
she  may  fly  from  such  as  are  disagreeable, 
dangerous,  or  hurtful,  and  pursue  such  as 
are  pleasant  and  useful  to  her  ;  and,  accor- 
dingly, she  is  supplied  with  muscles  and 
tendons,  the  instruments  of  motion,  which 
are  found  in  every  part  of  the  fabric  where 
motion  is  necessary  ;  but,  to  give  firmness 
and  shape  to  the  fabric  ;  to  keep  the  softer 
parts  in  their  proper  place  ;  to  give  fix- 
ed points  for,  and  proper  direction  to, 


Human  Frame.  239 

its  motions,  as  well  as  to  protect  some  of 
the  more  important  and  tender  organs 
from  external  injuries,  there  must  be 
some  firm  prop-work  interwoven  through 
the  whole  ; — and,  in  fact,  for  such  pur- 
poses the  bones  were  given.  The  prop- 
work  must  not  be  made  into  one  rigid 
fabric,  for  that  would  prevent  motion. 
Therefore,  there  are  a  number  of  bones^. 
These  pieces  must  all  be  firmly  bound  to- 
gether, to  prevent  their  dislocation  ;  and 
this  end  is  perfectly  answered  by  thet/zg*- 
aments.  The  extremities  of  these  bony 
pieces,  where  they  move  and  rub  upon 
one  another,  must  have  smooth  and  slip- 
pery surfaces  of  easy  motion.  This  is 
most  happily  provided  for  by  the  cartila- 
ges and  mucus  of  the  joints.  The  inter- 
stices of  all  these  parts  must  be  filled  up 
with  some  soft  and  ductile  matter,  which 
shall  keep  them  in  their  places,  unite 
them,  and  at  the  same  time  allow  them 
to  move  a  little  upon  one  another ;  and 

*  Dr.  Kezll  reckons  245  bones  in  the  human 
body,  others  make  them  to  be  249,  viz.  In  the 
skull  14,  in  the  face  and  throat  46,  in  the  trunk 
67.  in  the  arms  and  hands  62,  and  in  the  legs  and 
fcet  60. 


240  Human  Frame. 

these  purposes  are  answered  by  the  eel 
lar  membrane,  or  adipose  substance. — 
There  must  be  an  adequate  cover, 
over  the  whole  apparatus,  both  to  give  it 
compactness  and  to  defend  it  from  u 
thousand  injuries  ;  which,  in  fact,  arevthe 
very  purposes  of  the  skin,  and  other  in- 
teguments. Lastly,  the  mind  being  form- 
ed for  society  and  intercourse  with  be- 
ings of  her  own  kind,  she  must  be  endu- 
ed with  powers  of  expressing  and  com- 
mu  Bleating  her  thoughts  by  some  sensi- 
ble marks  or  signs,  easy  to  herself  and 
capable  of  great  variety  ;  and  accordingly 
she  is  provided  with  the  organs  and  fa- 
culty of  speech,  by  which  she  can  throw 
out  signs  with  amazing  facility,  and  van 
them  without  end. 

u  Thus  we   have  built  a  body  which 
seems  to  be  pretty  complete  ;  but,  as  it  is 
the  nature  of  matter  to  be  worked  upon 
and  altered  so,  in  a  very  little  time,  e. 
a  living  creature  must  1  'jyed,  if 

there  is  no  provision  for  repairing  the  in- 
juries which  she  will  commit  upon  her- 
self, and  those  which  she  ...Tposed 
to  from  without.  Therefore,,  a  treasure 
of  blwd  is  actually  '.e  heart 


Human  Frame.  24 jL 

and  vascular  system,  full  of  nutritious  and 
•.nicies,  fluid,  and  able  to  pene- 
trate into  the  minutest  parts  of  the  ani- 
mal ;  impeilfd  by  the  heart,  and  convey- 
ed by  the  arteries,  it  washes  every  part, 
builds  up  what  was  broken  down,  and 
sweeps  away  the  old  useless  materials. 
Hence  we  see  the  necessity  or  advan- 
tage of  the  heart  and  arterial  system. — - 
What  more  than  enough  there  was  of  the 
blood  to  repair  the  present  damages  of 
the  machine,  must  not  be  lost,  but  should 
be  returned  again  to  the  heart ;  and  for 
this  purpose  the  veins  are  actually  provid- 
ed. These  requisites  in  the  animal,  ex- 
plain a  priori,  the  circulation  of  the 
blood.  The  old  materials,  which  are  be- 
come useless,  and  are  swept  off  by  the 
current  of  the  blood,  must  be  separated 
and  thrown  out  of  the  system.  Therefore 
the  glands,  the  organs  of  secretion,  are 
given  for  straining  whatever  is  redun- 
dant, vapid,  or  noxious,  from  the  mass  of 
blood ;  and,  when  strained,  they  are 
thrown  out  by  entunctories,  called  organs 
of  excretion.  But  now,  as  the  machine 
must  be  constantly  wearing,  the  opera- 
tions must  be  carried  on  without  inter- 


242  Human  Frame. 

mission,  and  the  strainers  must  be  always 
employed;  therefore,  there  is  actually  a 
perpetual  circulation  of  the  blood,  and 
the  secretions  are  always  going  on.  Even 
all  this  provision,  however,  would  not  be 
-sufficient ;  for  that  store  of  blood  would 
be  soon  consumed,  and  the  fabric  would 
break  down,  if  there  were  not  a  provision 
made  for  fresh  supplies.  These  we  ob- 
serve in  fact  are  profusely  scattered  round 
her  in  the  animal  and  vegetable  king- 
doms ;  and  she  is  furnished  with  hands, 
the  fittest  instruments  that  could  have 
been  contrived,  for  gathering  them,  and 
for  preparing  them  in  a  variety  of  ways 
for  the  mouth.  But  these  supplies,  which 
we  call  food,  must  be  considerably  ch^ng- 
ed  ;  they  must  be  converted  into  blood. 
Therefore,  she  is  provided  with  teeth  for 
cutting  and  bruising  the  food,  and  with  a 
stomach  for  melting  it  down ;  in  short, 
with  all  the  organs  subservient  to  diges- 
tion. The  finer  parts  of  the  aliments  on- 
ly can  be  useful  in  the  constitution :  these 
must  be  taken  up  and  conveyed  into  the 
blood,  and  the  dregs  must  be  thrown  off* 
With  this  view,  the  intestinal  canal  is  ac- 
tually given.  It  separates  the  nutritious 


Human  Frame* 

part,  which  we  call  chyle,  to  be  conveyed 
into  the  blood  by  the  system  of  the  absor- 
bent vessels ;  and  the  feces  pass  down- 
ward out  of  the  body.  Thus  we  see  that, 
by  the  very  imperfect  survey  which  hu- 
man reason  is  able  to  take  of  this  subjects 
the  animal  man,  must  necessarily  be  com- 
plex in  his  corporeal  system,  and  in  its 
operations;  and  in  taking  this  general 
view  of  what  would  appear,  a  priori,  to 
be  necessary  for  adapting  an  animal  to 
the  situations  of  life,  we  observe,  with 
great  satisfaction,  that  man  is  according- 
ly made  of  such  systems,  and  for  such 
purposes.  He  has  them  all :  and  he  has 
nothing  more,  except  the  organs  of  respi- 
ration. Breathing  it  seemed  difficult  to 
account  for  a  priori ;  we  only  know  it  to 
be  a  fact  essentially  necessary  to  life. — > 
Notwithstanding  this,  when  we  see  all 
the  other  parts  of  the  body,  and  their 
functions  so  veil  accounted  for,  and  so 
wisely  adapted  to  their  several  purposes, 
there  would  be  no  doubt  that  respiration 
was  so  likewise  ;  and,  accordingly,  the 
discoveries  of  Doctor  Priestley  have  late- 
ly thrown  light  upon  this  function  also^ 
"  Of  all  the  different  systems  in  the 


244  Human  Frame. 

human  body  the  use  and  necessity  are  not 
more  apparent,  than  the  wisdom  and  con- 
trivance which  has  been  exerted  in  put- 
ting them  all  into  the  most  compact  and 
convenient  form  ;  in  disposing  them  so 
that  they  shall  mutually  receive  and  give 
helps  from  one  another ;  and  that  all,  or 
many  of  the  parts  shall  not  only  answer 
their  principal  end  and  purpose,  but  ope- 
rate successfully  and  usefully  in  a  varie- 
ty of  secondary  ways.  If  we  consider 
the  whole  animal  machine  in  this  light, 
and  compare  it  with  any  in  which  human 
art  has  exerted  its  utmost  skill  (suppose 
the  best  constructed  ship  that  ever  was 
built,)  we  shall  be  convinced,  beyond  the 
possibility  of  doubt,  that  there  exists  in- 
telligence and  power  far  surpassing  what 
human  art  can  boast  of.  Oae  superiori- 
ty in  the  animal  machine  is  peculiarly- 
striking.  In  machines  of  human  contri- 
vance, or  of  art,  there  is  no  internal  pow- 
er, no  principle  in  the  thing  itself,  by 
which  it  can  alter  and  accommodate  it- 
self to  any  injury  that  it  may  suffer,  or 
make  up  any  injury  that  admits  of  repair  ; 
but  in  the  natural  machine,  or  animal  bo- 
dy, this  is  most  wonderfully  provided  fo* 


Human  Frame*  243 

by  the  internal  powers  of  the  machine 
itself;  many  of  which  are  not  more  cer- 
tain and  obvious  in  their  effects,  than  they 
are  above  all  human  comprehension  as 
to  the  manner  and  means  of  their  opera- 
tion. Thus,  a  wound  heals  up  of  itself ; 
a  broken  bone  is  made  firm  by  a  callus  ; 
a  dead  part  is  separated  and  thrown  off; 
noxious  juices  are  driven  out  by  the 
emunctories  ;  a  redundancy  is  removed 
by  some  spontaneous  bleeding  ;  a  bleed- 
ing naturally  stops  of  itself;  and  a  great 
loss  of  blood,  from  any  cause,  is  in  some 
measure  compensated  by  a  contracting 
power  in  the  muscular  system,  which  ac- 
commodates the  capacity  of  the  vessel  to 
the  quantity  contained.  The  stomach 
gives  information  when  the  supplies  have 
been  expended,  represents  with  great  ex- 
actness the  quantity  and  quality  of  what 
is  wanted  in  the  present  state  of  the  ma- 
chine, and  in  proportion  as  she  meets  with 
neglect  rises  in  her  demand,  urges  her 
petition  in  a  louder  tone,  and  with  more 
forcible  arguments.  For  its  protection, 
an  animal  body  resists  hea't  and  cold  in 
a  very  wonderful  manner,  and  preserves 
an  equal  temperature  in  a  burning  and  i.i* 


246  Human  Frame. 

a  freezing  atmosphere.  These  are  pow- 
ers which  mock  all  human  invention  or 
imitation  ;  they  are  characteristics  of  the 
Divine  Architect!" 

Part  of  the  motions  of  the  complicat- 
ed frame  of  man,  in  common  with  all 
animated  beings,  are  voluntary,  or  de- 
pendent on  the  mind  f  and  part  mvohin- 
fari/^  or  without  the  mind's  direction. 

How  the  incorporeal  existence,  which 
we  call  mind,  can  operate  on  matter,  and 
put  it  in  motion,  is  to  us  perfectly  incom- 
prehensible. When  the  miatomist  con- 
siders the  number  of  muscles  that  must 
be  put  in  motion  before  any  animal  exer- 
tion can  be  effected ;  when  he  views 
them  one  by  one,  and  tries  to  ascertain 
the  precise  degree  to  which  every  indivi- 
dual muscle  must  be  constricted,  or  re- 
laxed, before  the  particular  motion  indi- 
cated can  be  effected, — he  finds  himself 
lost  in  the  labyrinth  of  calculations  in 
which  this  involves  him  ;  but  when  he 
considers  that  every  one  of  these  muscles 
must  be  constricted  or  relaxed  to  the  pre- 
cise degree  that  appertains  to  each,  and 
no  more,  and  at  the  same  instant  of  time  ; 
when  he  recollects,  that  the  smallest  jar- 


Human  Frame. 

ring  in  this  respect  in  any  one  of  these 
would  throw  the  whole  into  inextricable 
disorder  ;  when  he  considers  with  what 
promptitude  the  whole  of  this  is  done  in 
an  instant  by  the  mere  act  of  his  volition, 
and  how  in  another  instant,  by  a  change 
in  that  volition,  all  these  muscles  are 
thrown  into  a  different  state,  and  a  new 
set  brought  into  action,  and  so  on  conti- 
nually as  long  as  he  pleases,  his  mind  is 
lost  in  the  immensity  of  wonder  that  this 
excites.  But  when  he  farther  reflects, 
that  it  is  not  only  he  himself  that  is  en- 
dowed with  the  faculty  of  calling  forth 
those  incomprehensible  energies,  but  that; 
the  most  insignificant  insect  is  vested 
with  powers  of  a  similar  sort,  he  is  still 
more  confounded.,  A  skilful  naturalist 
has  been  able  to  perceive,  that  in  the  body 
of  the  poorest  caterpillar,  which,  in  the 
common  opinion,  is  one  of  the  most  de- 
graded existences  on  the  globe,  there  are 
upwards  of  two  thousand  muscles,  all  of 
which  can  be  brought  into  action  with  as 
much  facility  at  the  will  of  that  insect, 
and  perform  their  several  offices  with  as 
much  accuracy,  promptitude,  and  preci- 
sion, as  in  the  most  perfect  animal ; 


248  Human  Frame* 

all  this  is  done  by  that  insect  with  ati 
equal  consciousness  of  the  manner  how, 
as  the  similar  voluntary  actions  of  man 
are  effected. 

Nor  are  the  involuntary  motions  less 
mysterious  and  wonderful.  The  sto- 
mach, the  intestines,  and  all  the  functions 
necessary  to  life,  wait  not  to  be  called  in- 
to action  by  any  volition  of  ours.  The 
heart,  placed  near  the  centre  of  the  sys- 
tem, performs  its  task  as  well  ..when  we 
are  asleep,  as  when  we  are  awake,  by  night 
as  by  day,  and  like  an  unwearied  and 
iaithful  labourer,  with  muscular  exertions 
distributes  the  vital  stream  through  our 
complicated  frame,  'till  their  wearied 
functions  cease,  and  the  tenement  of  clay 
is  inhabited  no  more.  How  admirably 
It  is  calculated  to  keep  up  this  continued 
circulation  throughout  the  system  may 
be  understood  by  the  following  computa- 
tion by  Dr.  Keill:— u  Each  ventricle  will 
at  least  contain  one  ounce  of  blood.  The 
hearts  contracts  four  thousand  times  in 
one  hour  ;  from  which  it  follows,  that 
there  passes  through  the  heart,  every 
hour,  four  thousand  ounces,  or  three 
hundred  and  fifty  pounds  of  blood,  Now 


Human  Frame.  249 

the  whole  mass  of  bloed  is  said  to  be 
about  twenty-five  pounds,  so  that  a  quan- 
tity of  blood  equal  to  the  whole  mass  of 
blood  passes  through  the  heart  fourteen 
times  in  one  hour  ;  which  is  about  once 
every  four  minutes-"  Consider  what  an 
affair  this  is  when  wTe  come  to  very  large 
animals.  The  aorta  of  a  whale  is  larger 
in  the  bore  than  the  main-pipe  of  the 
water-works  at  London-Bridge  ;  and  the 
wat,er  roaring  in  its  passage  through  that 
pipe,  is  inferior  in  impetus  and  velocity 
to  the  blood  gushing  from  the  whale's 
heart.  Hear  Dr.  Hunter's  account  of  the 
dissection  of  a  whale.  u  the  aorta  mea- 
sured a  foot  diameter.  Ten  or  fifteen 
gallons  of  blood  is  thrown  out  of  the 
heart  at  a  stroke,  with  an  immense  velo- 
city, through  a  tube  of  a  foot  diameter. 
The  whole  idea  fills  the  mind  with  won- 
der." It  is  thus,  O  great  Author  of  all 
Things  !  we  discover  Thee  in  thy  works* 

OF    THE    FIVE    SENSES. 

Of  Seeing-. — The  organ  of  seeing  is 
the  Eye.  It  is  a  curious  and  most  won- 
derful piece  of  nature's  work>  admirably 
rontrived  with  various  coats^  muscles. 


Human  Frame. 

vessels,  and  humours  of  three  several 
>,  for  the  purpose  of  vision.  The 
first  humour  of  the  eye  is  called  the  aque- 
ous humour,  being  in  all  respects  like 
water,  hut  of  a  spirituous  nature  ;  for  it 
will  not  freeze  in  the  greatest  cold.  The 
second  is  called  the  crystalline  humour^ 
being  transparent,  and  more  solid  than, 
cither  of  the  other  ;  its  figure  resembles 
an  optic  lens,  convex  on  both  sides,  and 
its  use  in  the  eye  is  the  same.  Behind 
this  lies  the  vitreous  or  glassy  humour  ; 
it  is  very  much  like  the  white  of  an  egg  ; 
it  is  in  greater  abundance  than  either 
of  the  other  ;  it  gives  the  eye  its  spheri- 
cal form  ;  and  is  thicker  than  the  aque- 
ous, but  thinner  than  the  crystalline  hu- 
mour. Next  this  humour,  on  the  bot- 
tom of  the  eye,  is  spread  a  fine  curious 
rnembrane,  called  the  retina,  through 
which  are  expanded  the  medullary  fibres 
of  the  cpi'ic  nerve,  which  come  from  the 
brain.  Now  the  rays  of  light,  which 
come  from  all  parts  of  any  object,  falling 
upon  the  aqueous  humour  of  the  eye,  are 
through  it  refracted  to  the  crystalline  hu- 
humour,  by  which,  as  a  double  convex 
lens  (kept  always  at  a  proper  distance  by 


Human  Frame,  25 i 

the  glassy  humour)  they  are  all  converg- 
ed and  united  on  the  retina  ;  -the  impres- 
sion thereof  being  communicated  to  the 
common  sensory  of  the  brain  by  the  optic 
nerves,  doth  there  present  to  the  mind 
the  species  and  image  of  the  object. 

That,  which  immediately  affects  the 
sight,  and  produces  in  us  that  sensation, 
which  \ve  call  seeing,  is  light. 

Light  may  be  considered  either,  first, 
as  it  radiates  from  luminous  bodies  di- 
rectly to  our  eyes  ;  and  thus  we  see  lu- 
minous bodies  themselves,  as  the  sun,  or 
a  flame,  &c.  or,  secondly,  as  it  is  reflect- 
ed from  other  bodies  ;  and  thus  we  see 
a  man,  or  a  picture  by  the  rays  of  light 
reflected  from  them  to  our  eyes. 

Bodies,  in  respect  of  light,  may  be  di- 
vided into  three  sorts  ;  first,  those  that 
emit  rays  of  light,  as  the  sun  and  fixed 
stars  ;  secondly,  those  that  transmit  the 
rays  of  light,  as  the  air ;  thirdly,  those 
that  reflect  the  rays  of  light,  as  iron, 
earth,  &c.  the  first  are  called  luminous  ; 
the  second  pellucid ;  arid  the  third  opaque. 

Opaque  bodies  are  of  two  sorts,  specu- 
lar, or  not  specular.  Specular  bodies,  or 
mirrors ?  are  such  opaque  bodies  whose 


:252  Human  Frame* 

surfaces  are  polished  ;  whereby  they,  re- 
flecting the  rays  in  the  same  order  as  they 
come  from  other  bodies,  shew  us  their 
images. 

The  rays  that  are  reflected  from  opaque 
bodies  always  bring  with  them  to  the  eye 
the  idea  of  colour;  and  this  colour  is 
nothing  else  in  the  bodies,  but  a  disposi- 
tion to  reflect  to  the  eye  more  copiously 
one  sort  of  rays  than  another.  For  par- 
ticular rays  are  originally  endowed  with 
particular  colours  ;  some  are  red,  others 
blue,  others  yellow,  and  others  green,  &c. 

Every  ray  of  light,  as  it  comes  from 
the  sun,  seems  a  bundle  of  all  these  seve- 
ral sorts  of  rays  ;  and  as  some  of  them 
are  more  refrangible  than  others  ;  that 
is,  are  more  turned  out  of  their  course, 
in  passing  from  one  medium  to  another, 
it  follows,  that  after  such  refraction  they 
will  be  separated,  and  their  distinct  co- 
lour observed.  Of  these,  the  most  re- 
frangible are  violet,  and  the  least  red  ; 
and  the  intermediate  ones,  in  order,  are 
indigo,  blue,  green,  yellow,  and  orange. 
This  separation  is  very  entertaining,  and 
will  be  observed  with  pleasure  in  hold- 
ing a  prism  in  the  beams  of  the  sun. 


Human  Frame.  253 

As  all  these  rays  differ  in  refrangibili- 
ty7  60  they  do  in  reftexibilrty,  that  is,  in 
the  property  of  being  more  easily  reflect- 
ed from  certain  bodies,  than  from  others ; 
and  hence  arise,  as  hath  been  said,  ail 
the  colours  of  bodies,  which  are  in  a 
manner  infinite,  as  an  infinite  number  of 
compositions,  and  proportions  of  the 
original  colours  may  be  imagined. 

The  whiteness  of  the  sun's  light  is 
compounded  of  all  the  original  colours 
mixed  in  a  due  proportion. 

Whiteness,  in  bodies,  is  but  a  disposi- 
tion to  reflect  all  colours  of  light  nearly 
in  the  proportion  they  are  mixed  in  the 
original  rays  ;  as,  on  the  contrary,  black- 
ness, is  only  a  disposition  to  absorb  or 
stifle,  without  reflection,  most  of  the  rays 
•f  every  sort  that  fall  on  the  bodies. 

Besides  colour,  we  are  supposed  to 
see  figure  ;  but  in  truth,  that  which  we 
perceive  when  we  see  figure,  as  perceiv- 
able by  sight,  is  nothing  but  the  termina- 
tion of  colour. 

Of  hearing, — Next  to  seeing,  hearing 
is  the  most  extensive  of  our  senses.  The 
Ear  is  the  organ  of  hearing. 

Sounds  are  brought  to  the  ear  from  so 


254  Human  Frame. 

norous  bodies  by  means  of  the  ail- ;  and 
the  external  part  of  the  ear  is  so  contriv- 
ed, by  its  ridges  and  hollows,  that  sounds, 
being  gathered  into  it  as  into  a  tunnel, 
are  thereby  directed  to  the  meatus  audi- 
torious,  through  -which  they  pass  and 
strike  upon  a  thin  transparent  membrane 
of  an  oval  figure,  set  a  little  obliquely 
across  the  passage  of  the  ear ;  behind 
this  membrane  there  is  a  pretty  large  ca- 
vity, which,  with  the  said  membrane, 
from  its  resemblance,  is  called  the  tympa- 
num, or  drum  of  the  ear.  In  this  cavity 
are  four  small  bones,  which  from  their 
form  are  called  malleolus,  or  the  hammer  ; 
the  incus,  or  the  anvil ;  the  shapes*  or 
stirrup  ;  and  the  os  orbicculure,  or  circu- 
lar bone.  Within  the  tympanum  there 
are  several  other  cavities,  as  the  vestibu* 
him,  the  labyrinth,  and  the  cochlea  ;  these 
Internal  cavities  are  always  full  of  air ; 
wherefore  the  sounds  in  the  external  air 
striking  on  the  drum,  move  the  four  lit- 
tle bones  in  the  tympanum,  and  these  in 
like  manner  move  the  internal  air,  which 
maketh  an  impression  on  the  fine  bran- 
ches of  the  auditory  nerve  spread  through 
the  vestibulum,  the  winding  tubes  of  the 


Human  Frame,  23* 

labyrinth,  and  cochlea  ;  and  thus  all  re- 
fractions and  modulations  of  the  exter- 
ternal  air  become  perceptible,  and  conse- 
quently all  the  different  sounds  they  con- 
vey become  audible,  and  intelligible  to 
the  mind,  by  the  communication  of  these 
nerves  with  the  brain,  or  common  sensory* 

That  which  is  conveyed  into  the  brain 
by  the  ear,  is  called  sound,  though  in 
truth,  till  it  come  to  reach  and  affect  the 
perceptive  part,  it  be  nothing  but  motion* 

The  motion  which  produces  in  us  the 
perception  of  sound,  is  a  vibration  of  the 
air,  caused  by  an  exceeding  short,  but 
quick,  tremulous  motion  of  the  body  from 
which  it  is  propagated  ;*'  and  therefore  we 
consider  and  denominate  them  as  bodies 
sounding. 

That  sound  is  the  effect  of  such  a 
short,  brisk,  vibrating  motion  of  bodies 
from  which  it  is  propagated,  may  be 
known  from  what  is  observed  and  felt  in 
the  strings  of  instruments,  and  the  tremb- 
ling of  bells,  as  long  as  we  perceive  any 
sound  come  from  them ;  for  as  soon  as 
that  vibration  is  stopped,  or  ceases  in 
them,  the  perception  ceases  also. 

Of  Smelling. — Smelling    is    another 


256  Human  Frame* 

sense.  The  organ  of  smelling  is  trft  Nose 
The  cavity  of  the  nose  is  divided  into 
two  parts,  we  call  the  nostrils,  by  a  parti- 
tion, of  which  the  upper  part  is  bony, 
and  the  lower  cartilaginous.  The  upper 
part  of  the  cavity  is  covered  with  a  thick 
glandulous  membrane,  above  which  the 
olfactory  nerve  is  finely  branched  out  anc1 
spread  over  the  membrane  of  the  spon- 
gy bones  of  the  nose,  and  other  sinous 
cavities  of  the  nostrils.  Whence  the  ex- 
halations of  odours  entering  the  nostrils 
make  their  impressions  on  the  fibres  of 
the  nerves,  which  by  their  communica- 
tion with  the  brain,  excite  in  the  mine" 
the  smell  or  sensation  of  odours  of  eve- 
ry kind. 

Smelling  bodies  seem  perpetually  td 
send  forth  effluvia  or  steams,  without 
sensibly  wasting  at  all.  Thus  a  grain  of 
musk  will  send  forth  odoriferous  parti- 
cles for  scores  of  years  together,  without 
its  being  spent ;  whereby  one  would  con- 
clude that  these  particles  are  very  small  ; 
and  yet  it  is  plain,  that  they  are  much 
grosser  than  the  rays  of  light,  which  have 
a  free  passage  through  glass  ;  and  gros- 
ser also  than  the  magnetic  effluvia,  which 


Human  Frame.  25? 

pass  freely  through  ail  bodies,  when  those 
that  produce  smell  will  not  pass  ihe  thin 
membranes  of  a  bladder,  and  many  of 
them  scarce  ordinary  white  paper. 

There  is  a  great  variety  of  smelts, 
though  we  have  but  a  few  names  for 
them;  sweet,  stinking,  sour,  rank,  and 
musty,  are  almost  all  the  denominations 
we  have  for  odours  j  though  the  smell  of 
a  violet,  and  of  musk,  both  called  sweet> 
are  as  distinct  as  any  two  smells  whatso- 
ever. 

Of  Taste. — Taste  is  the  next  sense  to 
be  considered*  The  organ  of  -Taste  is 
the  Tongue. 

The  tongue  is  covered  with  two  mem- 
branes ;  the  external  is  thick  and  rugged, 
especially  in  beasts  ;  the  internal  me<m- 
brane  is  thin  and  soft ;  upon  it  appear  se- 
ver d\  papillae  or  small  risings,  like  the  tops 
of  the  small  horns  of  snails  ;  these  papil- 
lae are  made  of  the  extremities  of  the 
nerves  of  the  tongue,  and  piercing  the  ex- 
ternal membrane,  are  constantly  affected 
by  those  qualities  in  bodies,  which  have 
their  tastes  excited  in  the  mind  by  means 
of  these  nervous  papillae ;  and  thus  are 
these  papillae  the  immediate  organ  of 
tasting.  Y 


Human  Frames, 

It  may  be  observed  of  tastes,  tha* 
though  there  be  a  great  variety  of  them, 
yet,  as  in  smells, they  have  only  some  few 
general  names,  as  sweet,  bitter,  sour, 
harsh,  rank,  and  some  few  others. 

Of  Touch. — The  fifth  and  last  of  our 
senses  is  Touch  ;  a  sense  spread  over  the 
whole  body,  though  it  be  most  eminently 
placed  in  the  ends  of  the  fingers. 

By  this  sense  the  tangible  qualities  of 
bodies  are  discerned ;  as  hard,  smooth, 
rough,  clryr  wet,  clammy,  and  the  like. 

But  the  most  considerable  of  the  quali- 
ties that  are  perceived  by  this  sense  are 
Jieat  and  cold. 

The  due  temperament  of  those  two 
opposite  qualities  is  the  great  instrument 
of  nature,  that  she  makes  use  of,  in  most, 
if  not  all  her  productions. 

Heat  is  considered  by  some  as  merely 
the  consequence  of  a  very  brisk  agitation 
of  the  insensible  parts  of  the  object 
which  produces  in  us  that  sensation,  but 
it  is  most  generally  supposed  that  these 
effects  depend  on  a  certain  matter  called 
caloric,  or  the  matter  of  heat. 

Bodies  are  denominated  hot  and  cold 
in  proportion  to  the  present  temperament 


Human  Frame. 

of  that  part  of  our  body  to  which  they  are 
applied ;  so  that  feels  hot  to  one  which, 
seems  cold  to  another  ;  nay,  the  same  bo- 
dy felt  by  the  two  hands  of  the  same  man9 
may  at  the  same  time  appear  hot  to  .the 
one.  and  cold  to  the  other. 


26O        Human  Understanding* 


CHAP.  XIII. 

Of  the  Human  Understanding. 

THE  understanding  of  Man  is  what 
particularly  exalts  him  above  the  brute 
creation.  Though  some  of  the  most  sa- 
gacious of  animals  appear,  in  regard  to 
intellect,  in  certain  points  of  view,  to 
approximate  to  the  lowest  of  the  human 
species,  yet  there  can  be  no  doubt  that 
man  is  much  farther  exalted  above  them 
all,  than  any  one  of  these  excels  the 
next  below  it ;  for  though  many  of  the 
higher  orders  possess  a  kind  of  memo- 
ry, and  the  faculty  of  reasoning  in  a  cer- 
tain degree  ;  though  "  the  ox  knoweth 
his  owner,  and  the  ass  his  master's  crib," 
yet,  unless  it  be  in  recollecting  their  de- 
pendence on  others  for  food,  and  a  few 
circumstances  of  a  similar  nature,  ten- 
ding chiefly  to  the  preservation  of  exist- 


Human  Understanding.        261 

ence,  the  intellectual  powers  of  even  the 
highest  is  extremely  circumscribed. — 
The  dog  is  a  favoured,  and  a  very  saga- 
cious domestic  animal:  he  feels  the  be- 
nign influence  of  the  parlour  fire,  and 
enjoys  it  as  much  as  any  of  the  human 
gpecies  ;  but  he  never  can  be  made  senr- 
sible  of  the  uses  to  which  heat  may  be 
applied  in  changing  the  nature  of  bodies 
which  are  subjected  to  its  power  ;  he 
never  can  be  made  to  conceive  how  a 
piece  of  coal,  or  a  billet  of  wood,  can 
augment  the  heat,  and  continue  to  sup- 
port it ;  and  thus  he  cannot  spontaneous- 
ly feed  the  fire  when  occasion  shall  re- 
quire it ;  a  degree  of  reasoning  which  a 
child  acquires  almost  before  it  can  walk, 
and  which  even  an  idiot  knows.  In 
like  manner  the  elephant,  the  most  saga- 
cious of  the  brute  creation,  delights  in 
the  sugar-cane,  and  gives  evident  indica- 
tions that  this  is  a  food  which  he  relish- 
es in  the  highest  degree,  and  when  he 
once  discovers  where  it  is  to  be  found, 
will  expose  himself  to  any  danger  to  ob- 
tain it ;  but  .no  elephant  hath  ever  yet 
been  able  to  discover  that  if  the  joints, 
of  these  plants  be  buried  to  a  certain 
Y2 


262         Human  Understanding. 

depth  in  newly  turned  up  earth,  it 
there  revive,  and  send  up  shoots,  which 
in  due*  time  w;li  fiord  abundance  of  his 
favov.vjt;-  food.  This  kind  of  reasoning, 
thouga  it  be  the  most  obvious  to  all  man- 
kind, is  far  beyond  the  limited  faculties 
of  the  brute  creation.  It  is  man  alone 
who,  by  comparing  facts  that  fall  under 
his  cognizance,  and  reasoning  upon  them, 
has  been  enabled  to  subject  all  nature  to 
his  sv/ny.  Nor  is  it  alone  from  the  facts 
that  fall  under  his  own  observation  that 
he  derives  this  kind  of  knowledge  ;  by 
the  gift  of  language  he  has  it  communi- 
cated to  him  by  others,  or  transmitted  to 
him  from  the  experience  of  former  ages. 
"While  then  the  different  species  of  ani- 
mals universally  have  the  same  powers 
and  propensities  at  this  moment  that  they 
had  at  the  earliest  period  they  were 
known,  the  human  species  are  advancing 
from  age  to  age,  and  the  power  of  man, 
of  course,  gradually  extending  as  his 
knowledge  increases. 

Thus  is  man  by  the  faculties  of  his 
mind  pre-eminently  distinguished  from 
all  other  animals  ;  hut  as  he  comes  into 
the  world  without  any  idea  or  principle^ 


Human  Understanding.         263 

either  speculative  or  practical,  it  is  only 
by  the  cultivation  of  his  intellect  that  he 
can  fairly  claim  this  superiority  ;  there- 
fore leaving  this  part  of  our  subject,  we 
will  proceed  to  the  consideration  of  the 
distinct  operations  of  the  human  under- 
standing ;  define  its  powers,  and  show 
the  method  by  which  it  acquires  the 
stock  of  its  ideas,  and  accumulates  gen- 
eral knowledge. 

The  primary  faculty  of  the  mind  is 
Perception.  Perception  consists  in  the 
attention  of  the  understanding  to  the  ob- 
jects acting  upon  it,  whereby  it  becomes 
sensible  of  the  impressions  they  make  ; 
and  the  notices  of  these  impressions,  as 
they  exist  in  the  mind,  are  distinguished 
by  the  name  of  Ideas. 

Sensation  and  Refection  are  the  two 
fountains  or  sources  from  which  the  un- 
derstanding is  supplied  with  all  its  ideas, 
or  materials  of  thinking. 

Sensation  is  the  source  of  our  origin- 
al ideas,  and  comprehends  the  notices 
conveyed  into  the  mind  by  impulses  or 
impressions  made  upon  the  organs  of 
sense.  Such  are  the  perceptions  of  col- 
ours, sounds,  tastes,  &c.  We  derive  all 
Y3 


254         Human  Understanding. 

these  ideas,  numerous  as  they  are,  solely 
from  external  objects. 

Refection  is  the  mind's  perception  of 
its  own  faculties  and  operations.  Thus 
by  reflection  we  acquire  the  ideas  of 
thinking,  doubting,  believing,  &c.  which 
are  the  different  intellectual  operations 
represented  to  us  by  our  consciousness. 

A  proper  consideration  of  these  two 
sources  of  our  thoughts  will  give  us  a  clear 
and  distinct  view  of  the  nature  of  the  mind 
and  the  first  steps  it  takes  in  the  path  of 
knowledge.  The  mind  thus  stored  with 
its  original  notices  of  things,  has  a  power 
of  combining,moclifying,and  placing  them 
in  an  infinite  variety  of  lights,  by  which 
means  it  is  enabled  to  multiply  the  objects 
of  its  perception,  and  finds  itself  possessed 
of  an  inexhaustible  stock  of  materials  for 
refit  ction  and  reasoning.  And  it  is  to  be 
particularly  observed,  that  amongour  nu- 
merous discoveries,  and  the  infinite  vari- 
ety of  our  conceptions,  we  are  unable  to 
find  one  original  idea,  which  is  not  deri- 
ved from  sensation  or  reflection  ;  or  one 
complex  idea,  which  is  not  composed  of 
these  original  ones. 

The  ideas  with  which  the  mind  is  thus 


Human  Understanding.         26J 

furnished  are  either  Simple  or  Complex* 

Simple  Ideas  are  such  as  exist  in  the  mind 
under  one  uniform  appearance,  and  can- 
not be  divided  into  two  or  more  ideas  > 
for  example,  a  colour,  a  sound. 

Complex  Ideas  consist  of  several  simple 
Ideas  united  in  the  same  representation, 
appearance  or  perception;  and  they  either 
come  into  the  mind  thus  united  from  the 
operation  of  things  without  us,as  the  idea, 
solidity  and  figure,  is  caused  by  the  same 
ball ;  therefore  in  the  complex  idea  of  the 
ball  we  conceive  such  ideas  as  co-existent 
and  concomitant ;  or  else  when  such  sim- 
ple ideas  are  united  by  the  mind,  as  in  the 
idea  of  law,  obligation,  £^c. 

In  the  production  of  Complex  Ideas 
which  are  formed  at  the  pleasure  of  the 
mind,  it  exerts  three  voluntary  acts,  viz* 
Co mposition,Abstr  action,  and  Comparison* 

Composition  is  joining  together  two  or 
more  Simple  Ideas,  and  considering  them 
as  one  picture  or  representation.  By 
composition  we  have  the  ideas  of  num- 
ber, extension,  &c. 

Abstraction  is  separating  from  a  par- 
ticular idea  those  circumstances  which 
render  it  the  representative  of  a  single 


266         Human  Understanding* 

determinate  object,  and  thereby  making 
it  to  denote  a  whole  rank  or  class  of  things. 
Hence  we  acquire  Universal  Ideas,  such 
as  whiteness,  beauty,  melody,  &c. 

Comparison  is  bringing  two  or  more 
ideas  into  the  view  of  the  mind,  and  ex- 
amining their  mutual  correspondencies* 
By  comparison  we  gain  our  ideas  of  Re- 
lations, which  are  proportional,  as  equal, 
more,  less,  Sec.  or  natural,  as  father, 
mother,  &c.  or  civil,  as  king  and  people,, 
general  and  army,  &c. 

This  division  of  our  ideas,  as  it  seems 
to  be  the  most  natural,  and  truly  to  rep- 
resent the  manner  in  which  they  are  in- 
troduced into  the  mind,  will  be  found  to 
include  them  in  all  their  varieties. 

We  know  that  our  thoughts,  although 
so  numerous  and  manifold,  are  all  con- 
tained within  our  own  breasts,  and  are  in- 
visible. But  as  men  were  not  created  to 
live  solitarily,  or  independently  of  each 
other,  we  are  provided  with  organs  pro- 
per for  framing  articulate  sounds,  and  a 
capacity  of  using  those  sounds  as  signs  of 
internal  conceptions.  From  hence  are 
derived  words  and  language.  For  any 
sound  being  once  determined  upon  to 


Human  Understanding.         26JT 

stand  as  the  sign  of  an  idea,  custom  by 
degrees  establishes  such  a  connexion  be- 
tween them,  that  the  appearance  of  the 
idea  in  the  understanding  always  brings 
to  our  remembrance  the  name  by  which 
it  is  expressed  ;  and  in  like  manner  the 
hearing  of  the  name  never  fails  to  excite 
the  idea  which  it  is  intended  to  denote. 
This  connexion  between  words  and  ideas, 
however,  is  perfectly  arbitrary,  and 
dependent  on  custom. 

By  language  we  are  enabled  to  define 
our  ideas.  Definition  is  "  the  showing 
the  meaning  of  one  word  by  several  oth- 
er not  synonymous  terms."  And  here  it 
may  be  observed,  that  Simple  Ideas  can- 
not be  defined,  since  definition  is  resol- 
ving the  thing  to  be  defined  into  its  most 
simple  ideas  ;  but  Complex  Ideas  may  be 
defined,  because  they  may  be  resolved  in- 
to their  simple  ideas.  Definition  furnish- 
es us  with  the  fittest  means  of  communica- 
ting our  thoughts  ;  for  if  we  were  unable 
to  impart  our  Complex  Ideas  to  each  oth- 
er by  the  aid  of  definition,  it  would  in  ma- 
ny cases  be  impossible  to  make  them 
known.  This  is  evident  in  those  ideas 
which  are  solely  the  offspring  of  the  min(l» 


268         Human  Understanding*. 

For  as  they  exist  only  in  the  understand- 
ing, and  have  no  real  objects  in  nature,  in 
conformity  to  which  they  are  framed,  if 
\ve  could  not  communicate  them  to  others 
by  description,  they  must  be  confined  to 
the  narrow  limits  of  a  single  mind.  All 
the  beautiful  ideas  formed  by  the  fancy  of 
a  Shakspeare  or  a  Milton,  without  the 
faculty  of  displaying  them  by  words, 
would  never  have  extended  their  influence 
beyond  their  own  breasts. 

All  language  may  be  resolved  into 
Nouns  and  Verbs ,  with  their  respective 
Abbreviations. 

Nouns  express  names  of  things  :  they 
are  divided  into  Substantives,  which  are 
the  principal  things  spoken  of ;  and  Ad- 
jectives, which  denote  qualities,  or  cir- 
cumstances belonging  to  them. 

Verbs  express  modes  of  existence. 
They  are  of  three  kinds,  such  as  denote 
simple  existence  ;  for  example,  to  be  ; 
such  as  express  existence  in  an  active 
state,  for  example,  to  eat :  and  such  as 
express  existence  in  a  passive  state  ;  as, 
to  be  eaten. 

Words  which  are  usually  represented  as 
indeclinable  particles  having  no  deter- 


Human  Understanding.        269 

minate  signification  of  their  own,  are  Ab- 
breviations of  Nouns  or  Verbs,  invented 
for  the  greater  expedition  of  commuica- 
ting  our  thoughts.  Thus  If  signifies 
give,  and  signifies  add,  being  impera- 
tives of  corresponding  verbs.  See  this 
theory  of  language  stated  and  evinced  in 
Mr.HorneTooke's  Diversions  of  Purley. 

Having  thus  considered  our  ideas, 
which  are  the  materials  of  our  knowledge, 
and  our  language,  which  is  the  manner 
of  our  conveying  them  to  others  ;  the 
last  thing  is  to  consider  how  our  ideas 
are  put  together,  and  compared  one  with 
the  other. 

And  herein,  First,  of  Knowledge. 

Knowledge,  which  is  the  highest  de- 
gree of  the  speculative  faculties,  consists 
in  the  perception  of  the  connexion  and 
agreement,  or  disagreement  and  repug- 
nancy of  our  ideas. 

This  perception  is  either  immediate  or 
mediate.  Immediate  perception  of  the 
agreement  or  disagreement  of  two  ideas, 
is  when,  by  comparing  them  together  in 
our  minds,  we  see,  or,  as  it  were,  we 
behold  their  agreement  or  disagreement. 
This  therefore  is  called  Intuitive  Know- 


27O         Human  Understanding, 

ledge.  Thus  we  see  that  red  is  not  green  -9 
that  the  whole  is  bigger  than  a  part ;  that 
two  and  two  are  equal  to  four. 

The  truth  of  these  and  the  like  propo- 
sitions we  know  by  bare  simple  intuition 
of  the  ideas  themselves,  without  any  more 
ado ;  and  such  propositions  are  called 
self-evident. 

The  mediate  perception  of  the  agree-, 
ment  or  disagreement  of  two  ideas,  is, 
when  by  the  intervention  of  one  or  more 
other  ideas,  their  agreement  or  disagree- 
ment is  shewn.  This  is  called  Demon- 
stration or  Rational  Knowledge.  For 
instance,  the  inequality  of  the  breadth 
of  two  windows,  or  two  rivers,  or  any 
two  bodies  that  cannot  be  put  together, 
may  be  known  by  the  intervention  of 
the  same  measure  applied  to  them  both ; 
and  so  it  is  in  our  general  ideas,  whose 
agreement  or  disagreement  may  be  often 
shewn  by  the  intervention  of  some  other 
ideas,  so  as  to  produce  demonstrative 
knowledge,  where  the  ideas  in  question 
cannot  be  brought  together,  and  immedi- 
ately compared,  so  as  to  produce  intui- 
tive knowledge. 

Secondly,  Of  Judgment. 


Human  Understanding. 

judgment  is  that  faculty  which  is  giv- 
en man  to  supply  the  want  of  clear  and 
certain  knowledge,  where  that  cannot  be 
had.  It  consists  in  putting  ideas  togeth- 
er, or  seperating  them  from  one  another 
in  the  mind,  when  their  certain  agree- 
ment or  disagreement  is  not  perceived, 
but  presumed  to  be  so  ;  which  is,  as  the 
word  imports,  taken  to  be  so  before  it 
certainly  appears. 

Hence  the  understanding  doth  not  on- 
ly know  certain  truth,  but  also  judges  of 
•probability*  Probability  is  always  con- 
versant about  propositions  whereof  we 
have  no  certainty,  as  in  knowledge,  but 
only  some  inducements  to  receive  them 
as  true  ;  such  as  their  conformity  to  our 
own  knowledge,  observation  and  experi- 
ence ;  and  the  entertainment  the  mind 
gives  this  sort  of  propositions  is  called 
assent,  opinion  or  belief. 

Of  probability  there  are  various  de- 
grees, from  a  moral  certainty  to  the 
slightest  degree  of  evidence  ;  and  the 
degrees  of  assent  are  proportionably  va- 
rious, from  the  least  deviation  from  the 
equilibrium  to  the  lowest  degree  upon 
the  scale  of  evidence,  and  even  to  amor- 
al impossibility* 


272         Human  Understanding, 

Lastly,  Of  Reason. 

Reason  is  the  pre-eminent  faculty  of 
the  human  mind,  and  is  necessary  and 
assisting  to  all  our  other  intellectual  fa- 
culties. By  it  we  enlarge  our  know- 
ledge and  regulate  our  assent ;  for  it  hath 
to  do  both  in  knowledge  and  opinion, 
and  is  the  faculty  which  finds  out  the 
means,  and  rightly  applies  them,  to  dis- 
cover certainty  in  the  one,  and  probabil- 
ity in  the  other.  It  is  Reason  which 
perceives  the  necessary  and  indubitable 
connexion  of  all  the  ideas  and  proofs  one 
to  another,  in  each  step  of  any  demon- 
stration that  produces  knowledge  ;  it  like- 
wise perceives  the  probable  connexion 
of  all  the  ideas  or  proofs  one  to  another, 
in  every  step  of  a  discourse  to  which  it 
will  think  assent  due  ;  and  where  the 
mind  does  not  perceive  this  probable 
connexion  or  no  ;  there  men's  opinions 
are  not  the  product  of  Judgment,  or  the 
consequence  of  Reason,  but  the  effects 
of  chance,  and  of  a  mind  floating  at  all 
adventures,  without  choice,  and  without 
direction* 

FINIS. 


